Adium X

http://www.adiumx.com/

Free. An instant messaging client which can talk to just about every service out there (Jabber, Aim, Google Talk, Facebook Chat, Twitter, etc.). It is also extremely customizable.

Alternatives: Apple’s Messages (previously iChat) has evolved to the point that it can give Adium a run for its money, especially if you need phone-based text messaging thrown into the mix.

Air Video Server

http://www.inmethod.com/air-video/

Free. This unobtrusive server allows you to stream video from your Mac to an iOS device on the same network. It supports a number of formats, converting them while streaming if necessary. To watch the video, your iOS device needs a specific client application (a free, limited version, or a $3 full version).

Alfred

http://www.alfredapp.com/

Free. Once you use an application like Alfred to launch applications, open files and search, you have a hard time using machines that don’t offer something similar. Its description as a “productivity application” doesn’t do much to tell you what it does, which is a bit hard to explain. The basic idea is that you use a hot key combination (option-space, by default) to pop up a window, then type a few characters to do all sorts of stuff. It is best examined by installing it and trying it out. Alfred has a £15 PowerPack that extends its functionality, but it is perfectly usable without it.

Alternatives: When it looked like Quicksilver was dead, I spent some time looking at Quicksilver alternatives.

AppleJack

http://applejack.sourceforge.net/

Free. You may never actually need AppleJack, but when you do, it will save your ass. AppleJack is a boot-time, command-line tool that can do things like disk repair and so on, without needing a second startup disk. It’s also much easier to use than similar tools I’ve seen. It operates in single user mode (which, as I continually forget, is accessed by holding down command and s while booting).

Battery Health

http://www.fiplab.com/

Free. If you have a laptop, keeping this app running in the background gives you a decent picture of what your battery is up to, and how well it is aging.

Bricksmith

http://bricksmith.sourceforge.net/

Donationware. Bricksmith allows you to create virtual instructions for your Lego® creations. The app is based on the LDraw library, a collection of 3D models of Lego building blocks created by enthusiasts from around the world. My recommendation of this software should be considered biased, since I contribute code to it every once in a while. If you use this software to build models, you might also be interested in LDView, LPub and POV-Ray.

Chmox

http://chmox.sf.net/

Free. It is rare that you actually need to be able to read a Microsoft help archive file (a *.chm file) on a Mac, but occasionally you find some good reference material in that format. This reader can open and display such files, all in a Mac-like way. Simple, but effective.

ClamXav

http://clamxav.com/

Free. Viruses have never been that big of a problem on the Mac. Up through Mac OS 9, there were only a handful of known virii, only a couple of which were dangerous. So far, even fewer have targeted Mac OS X. Still, Macs can hold files that contain virii from other platforms (such as the tens of thousands of them that can affect Office documents on Win32 machines) and pass them on. Your Win32 friends will thank you not to send them any, and this program can find and kill them. Watching this scan your junk mail folder is educational.

DiffPDF

http://www.qtrac.eu/diffpdf.html

Free. Depending on how often you work with .pdf files, you may need a utility to compare the contents of two different versions. While not perfect, this does a fairly decent job of graphically displaying what has changed between two versions. This is really a Linux utility, but if you dig through the page linked to above, you should find a link to a Mac version.

EasyFind

http://www.devontechnologies.com/products/freeware.html

Free. OS X has a built-in feature for searching files called Spotlight. This feature has come a long way since it was first introduced. If you view all results on Mountain Lion, for example, you can click the + button at that top to add all sorts of filtering to the results, a big improvement over its initial incarnation. Still, sometimes you need even more power, which this app can provide.

Alternatives: Both DataLore and HoudahSpot are more powerful than EasyFind, for a price.

Eclipse

http://www.eclipse.org/

Free. Widely regarded as just a Java IDE (a task at which it is unrivaled, in my opinion), Eclipse is really more of a platform into which functionality can be plugged. The Java plugins happen to be bundled with the download, but there are others that extend Eclipse to be much more, such as the ability to write and debug Perl and all sorts of other stuff.

File Merge

http://developer.apple.com/tools/macosxtools.html

Free. A gem hidden among the Mac OS X development tools, this is a slick text file comparison application. Almost as good as the one built into CodeWarrior once upon a time, but free. Downloading the dev tools requires a free registration with Apple.

Fink

http://fink.sourceforge.net/

Free. Provides downloading, installation and management of nearly 5000 open source Unix programs, compiled and tested under Mac OS X. If you are a Linux or Unix user looking to get your favorite tool onto your new Mac, check out Fink first. Most likely, someone has already gone through the pain of porting it for you.

Alternatives: Several other projects aim to do the same thing that Fink does, including Homebrew, Rudix and MacPorts.

Fluid

http://fluidapp.com/

Free. Fluid allows you to wrap a particular web page up as a distinct application. For example, if you use GMail (or Facebook, Campfire, Pandora, etc.), you can build a GMail app that is nothing but a dedicated browser containing just the GMail experience, but is treated as a first class application by the OS. Fluid uses WebKit, so provides the same experience that Safari would. There is also a $5 version that gives you a few other bells and whistles (e.g. full screen application).

Full Deck Solitaire

http://www.grlgames.net/page9/

Free. The most used Windows application is Solitare, and switchers might go into withdrawal, since no solitaire application ships with OS X. In the broader ecosystem, however, you have quite a few to choose from on the OS X side of things, but this seems to be the best.

GeekTool

http://projects.tynsoe.org/en/geektool/

Free. A strange little application, GeekTool allows you to display various kinds of information (mostly output of unix scripts) on your desktop. This doesn’t sound like much, but you can do some clever things with it.

Go2Shell

http://alicedev.com/go2shell

Free. This app integrates into the Finder (by dragging the app into the Finder’s toolbar…yes, you can do that). Once so installed, any time you click it in the toolbar, a terminal will be opened, with the working directory set to the directory currently displayed in the Finder window.

HandBrake

http://handbrake.fr/

Free. The only DVD ripper you’ll ever need. Though it has every tweakable setting you’d ever want, it hides this power under a simple interface, with presets for iPods, AppleTVs and so on. It can also handle multiple audio tracks, subtitles and so on. If you happen to have a Blu-Rray drive, however, HandBrake cannot read it directly.

IPSecuritas

http://www.lobotomo.com/products/IPSecuritas/

Donationware. This IPSec client allows your Mac to connect to virtual private networks (VPNs). Though not the most intuitive interface on Earth, it gets the job done. If you have a home router capable of creating a VPN, you can use this client to access your home network while you are at work or on the road.

iTerm

http://www.iterm2.com/

Donationware. While the Mac comes with a serviceable command line application called Terminal, this replacement for it goes a bit farther, adding support for split panes, better searching, full screen support, and so on. I wish it supported integration with a password manager, but no such luck (yet).

Light Table

http://www.lighttable.com/

Free. Development of this experimental integrated development environment (IDE) is funded by a Kickstarter project and seeks to provide a “work surface” for real-time programming, rather than windows and nested frames of most IDEs. The tool is still in the alpha stages, but supports Python, Javascript, CSS, HTML and Clojure at present. Play around with it.

MetaX

http://www.kerstetter.net/index.php/projects/software/metax

Free. Allows you to edit the metadata (title, episode id, cover art, etc.) of video files. It offers much more advanced controls and option than similar tools in iTunes, and writes them permanently into the video file (which iTunes does not do), so if you move the file to another computer, the metadata goes with it. Under the hood, it uses the Atomic Parsley command-line tool, and it can make use of services like tagChimp to download metadata for millions of titles.

NeoOfficeJ

http://www.neooffice.org/

Free. While the OS X version of Microsoft’s Office for Mac finally contains first class Mac applications again (for a while, the Mac versions were terrible), the suite remains pricy. NeoOfficeJ offers a version of OpenOffice, but built with a native Mac look and feel. While not quite as polished as Office for Mac, this app is file compatible with it, and infinitely cheaper. Note that, like OpenOffice, NeoOfficeJ is a Java application.

Alternatives: Apple’s iWork suite is reasonably priced, offers iPad versions of the apps, and has the advantage of offering its applications separately, but the experience is a bit different than Office for Mac. Keynote is flat-out better than PowerPoint. Pages is a bit more of a page layout program and a bit less of a word processor than Word. Numbers is a curious beast that is sort of spreadsheet like, but not really the same thing as Excel.

Onyx

http://www.titanium.free.fr/downloadonyx.php

Free. A general purpose utility for setting various (otherwise hidden) options in Max OS X, such as dock “pinning” and drop shadows, permission repairing, logs, etc.

Prey

http://preyproject.com/

Free. Both software and a service, installing Prey allows you to track your Mac if it gets stolen. When you install it, you register on Prey’s web site, which is used to mark a machine as “missing” and do other setup. When so marked, your machine will send reports to Prey about the machine’s location, even pictures from its webcam, to the web site. The software is free and the service allows tracking of three devices for free. You can also install prey on smartphones, so, if you have a lot of devices, you might need to pay for more advanced service.

Alternatives: Apple’s Find My Device is bundled into most of their devices now.

QuickLook CSV plugin

https://code.google.com/p/quicklook-csv/

Free. This quick look plugin not only displays a popup preview of data in comma-separated value (csv) and tab delimited files, but also changes their icon into a rough rendering of what the document looks like.

SimpleMovieX

http://simplemoviex.com/SimpleMovieX/

Free. If you rip your DVDs or record from television, you may find you have a need for some lightweight editing of the results, such as trimming out commercials, eliminating the same annoying opening credits from every episode of a TV series, concatenation of several videos in a row, adding/removing/renaming chapters, and so on. SimpleMovieX is built for this kind of quick video work.

SiteSucker

http://sitesucker.us/mac/mac.html

Free. Sometimes you just need to download an entire web site at once. This software provides a fairly intuitive way of doing so, with a handful of options to tune for a particular site..

Alternatives: The previously recommended WebDevil provides a bit more power, but is expensive. The command line app wget can also do some types of whole site downloading.

Skim

http://skim-app.sourceforge.net/

Free. A slim-but-powerful PDF reader. Unlike Acrobat Reader, it supports the new Retina displays. Unlike Preview (which comes free with OS X), it allows you to control if the first page is single or double when in two-page display mode, and its full page mode is less flickery. It also has note-taking capabilities, so you can add annotations to PDFs.

SourceTree

http://sourcetreeapp.com/

Free. If you need a dedicated graphical client for distributed revision control systems (DVCS) like Git or Mercurial, SourceTree is the weapon of choice. While Git plugins are available for Eclipse (see above), the dedicated nature of this app makes using these services a bit easier.

Suspicious Package

http://www.mothersruin.com/software/SuspiciousPackage/

Free. While most software downloads no longer require installers (just dragging an app to a folder), sometimes files need to go in particular places, so you get an installer package. You can never really tell what is in such packages, unless you have this quick look extension installed. Click once on the package, hit space, and get a popup window listing everything inside the package.

Transmission

http://www.transmissionbt.com/

Free. With the large number of BitTorrent clients available on the Mac, with different release schedules, something as subjective as which is one is “best” tends to ebb and flow. Last I looked, this was the client that worked for me, with a clear interface that did what I asked it to. Since I keep an old machine under my desk that is more or less dedicated to things like BitTorrent, I also appreciate that this app publishes a browser-based interface so other machines on my LAN can control it.

Alternatives: The µTorrent client now runs on the Mac and has a number of users who converted from Transmission. Xtorrent seems more feature rich, but isn’t free.

Video Monkey

http://videomonkey.org/

Free. Once there was an application called VisualHub, which rose above the sea of batch video conversion applications on the Mac to become both powerful and (very) easy to use. (Plus, it’s icon, an amalgam of a film strip and the Rosetta Stone was totally brilliant.) Then, its creator gave up. What followed was a long chain of forks, clones, bizarre patches and dead ends, with names like iSquint, Transcoder Redux (at several different places) and FilmRedux. Video Monkey is the only free app to emerge from the ashes that captures the essence of VisualHub. It also adds the ability to add metadata as part of the conversion.

Alternatives: A more direct ancestor to VisualHub is ReduxEncoder, which looks to be similar to Video Monkey, but costs £2. Even more expensive, but perhaps a bit more polished is Permute. Some of the other applications in this list (e.g. HandBrake, VLC) can also convert video, but don’t handle batches well. RoadMovie is also worth a look (even though it is $30), as it combines metadata editing with batch video conversion.

Vienna

http://www.vienna-rss.org/

Free. Prior to the rise of social networks, Really Simple Syndication (RSS) was all the rage. Now it seems like many have never even heard of it, and Google is killing the service that many RSS readers use for syncing. It still works the way I do, though, (and social networking mostly doesn’t) so I’m still an RSS junky. This open source reader is simple, and does just enough for me. Recently, they added Google Reader syncing (oops), so if anyone builds a decent replacement for the API, chances are it will get updated to use it.

Alternatives: I’ll like continue to use Google Reader until it dies on July 1, 2013. It looks like Feedly might be able to replace it. These are both browser-based. For Mac app solutions, Reeder has a lot of fans, but is also leveraged heavily into the Google Reader API.

VLC

http://www.videolan.org/vlc/

Free. A video player that can play more formats than the default QuickTime installation provides (including AVI, MKV and divx). There are some iOS apps which can act as a remote control for playback in VLC as well.

Vue Pioneer

http://www.e-onsoftware.com/products/vue/vue_pioneer/

Free. Vue creates 3D scenery using fractal terrain and can add trees as well, with photorealistic rendering of the whole scene. It is part of a cross-platform suite of products that get more powerful as they get more expensive.

Alternatives: Terrain rendering apps seem to leapfrog each other regularly and target different markets. You might find that Bryce (which would get my recommendation instead of Vue Pioneer if it were able to run on Lion or beyond), TerraRay, Terragen, one of Vue’s more expensive brethren or Daz Studio work better for you.

Wireshark

http://www.wireshark.org/

Free. Wireshark is a cross-platform network packet analyzer, with pretty good visualization, decent documentation and a legion of users.

1Password

http://1passwd.com/

$30. Since the authors of 1Password removed WiFi syncing with iOS, I have a hard time recommending this as unequivocally as I did before (even if they do eventually offer some USB based sync). Still, this application will change the way you use the web. Since it seamlessly integrates into major browsers, any time you create an account on a web site, you use 1Password to generate and store a completely random and unique password for that site. When you go back to the site, 1Password remembers that password for you. So, you get to be secure, without the hassle of remembering huge numbers of passwords yourself. The application also can track serial numbers for software, credit card numbers and so on, all stored strongly encrypted. It does support Dropbox syncing; however, even with encryption it strikes me that transmitting all of your passwords in the cloud is a really bad idea, so I don’t use that feature.

Alternatives: A number of other password managers exist, many which do have wifi syncing. Few offer browser integration (yet), which is the feature that makes 1Password useful. The most promising of these is STRIP, which was found to be more secure than 1Password. The cross-platform mSecure is also a contender.

Bartender

http://www.macbartender.com/

$15. More and more apps these days clutter up your menu bar with status icons. Most of these icons can be turned off, but some can’t, and some are still useful. Bartender allows you to collect all these menu bar items into a submenu of sorts, with full control over which items go where. It offers a four week free trial.

BetterZip

http://macitbetter.com/

$20. While OS X comes with a number of ways to work with zip files, BetterZip is, well, better at more complex work, particularly for exploring contents of an archive without decompressing it. BetterZip can also decompress other compression formats, such as .tar and .rar, including most traditionally Mac types like .sit. As a separate download, it also supplies a quick look extension that shows the contents of a zip archive.

Cheetah 3d

http://www.cheetah3d.com/

$99. While quite a few 3d editors exist on the Mac, Cheetah is one of the few designed specifically for it. It’s UI is powerful, but more intuitive that other 3d packages I’ve tried (user interface in 3d packages tends toward the bizarre). The latest version (6.x) also seems to be collecting a bunch of 5-out-of-5 ratings from all over the place.

Alternatives: Some free 3d suites are popular but not as easy to use, particularly Blender and DAZ Studio. Prices get nuts on the higher end with Maya.

Coda

http://www.panic.com/coda/

$79. Until Coda, there were two basic methods of creating web sites. One way was to use a WYSIWYG tool like Sandvox or RapidWeaver. The other was to do hand coding using a mix of various tools, like text editors, file transfer programs, CSS editors and various browsers. Coda attempts to change this (and succeeds pretty well), providing a tool for the “hand markup” set that vastly streamlines workflow, and essentially obsoletes about a half-dozen other tools. Panic Software allows a 30-day trial before requiring payment, with a small discount if you own other Panic titles.

Alternatives: Coda has spawned some imitators, mostly developers of the aforementioned “various tools”, who are trying to turn their tool into a more widely encompassing platform, such as the way CSSEdit 3 has mutated into Espresso. The cross-platform Aptana isn’t as slick looking, but seems plenty powerful and is free.

Daisy Disk

http://www.daisydiskapp.com/

$10. The evolution of graphically investigating what is taking up your hard drive space, using a “sunburst” style of display which seems more natural than the “heat map” style of some of the alternatives. This software also handles the little details very well, making it very intuitive.

Alternatives: Applications like Disk Inventory X do a similar job for free, but with less polish. DiskWave provides even less polish, but is also free.

Delicious Library

http://www.delicious-monster.com/

$40. For the anal-retentive in you, this tracks collections of books, DVDs, CDs and games. Integrates with a bar-code scanner, if you happen to have one (such as a hacked CueCat). Also allows you to use a video camera to scan barcodes. Can enter ISBN or USP numbers and will lookup information on item on the net. Library allows only 25 items to be entered unless you pay for it.

Alternatives: Inventory managers can be found all over the place. Most of them are terrible. One free offering that seems to, at least, have rough feature parity with Delicious Library is Data Crow.

DupeZap

http://www.hyperbolicsoftware.com/DupeZap.html

$5. It turns out to be fairly easy to wind up with duplicate copies of files, particularly if you collect certain types of data (say, comic book files or role-playing pdfs). This application will hunt for duplicate files and let you delete extras; however, pay careful attention to what it finds. If you are not sure what it is doing, you can get burned.

Alternatives: Gemini, DupeZap Plus (basically DupeZap 2, but more expensive); TidyUp (even more features and cost).

Escape Velocity: Nova

http://www.ambrosiasw.com/games/evn/

$30. A role-playing/space combat game that is sort of hard to explain until you play it. The makers of this game, Ambrosia, completely rule. If this genre is not your cup of tea, I guarantee that they have another game (some of which, alas, only run in Classic mode) that will have you addicted within minutes. If you like this game, you might also try Vendetta, which is very similar in concept, but uses 3D first-person combat and requires on-line play with thousands of other players.

GraphicConverter X

http://www.lemkesoft.de/en/graphcon.htm

$30. Capable of reading and writing nearly any graphic format, this program also has slide show capability and a great directory-based image browser. A suite of batch processing tools also make altering multiple files the same way mostly painless. (For example, take a huge directory of images, scale them all to be the same height, then crop them to be the same width, then save them as a different format.)

Growl

http://growl.info/ (app store)

$4. Growl is a notification system used by a lot of the other apps on this list to breifly popup a message in the corner of your screen to alert you to an event (such as e-mail arriving, a job completing, and so on). Though previously free, the developer has now fully embraced the App Store model.

Alternatives: Mountain Lion’s new Notification Center is aimed squarely at out-growling Growl. For the moment, more apps support Growl.

Icon Creator

http://mediaware.sk/iconcreator

$4. Once upon a time, the Mac developer tools came with Icon Composer, a simple application for editing application icons. In the early days of OS X development, Apple had to build quick and dirty tools like this, since they were the only show in town. Now that third parties build much better icon editors than Apple could, they have discontinued Icon Composer. This is probably the best of its replacements, mainly for its exporting capabilities. (Also, when I asked the author to add change the open dialog to allow browsing inside application packages, he released a new version that did so within days. This made creating this post much easier.)

Alternatives: Iconographer (free, but abandoned); IconBuilder (Photoshop integrated filter).

iBank

http://www.iggsoftware.com/ibank/

$60. Even back before the OS X era, Mac’s had a surprisingly large number of finance managing applications, with Quicken eventually emerging as the dominating force. Quicken screwed up, though keeping its code mired in technology known to be dying. When this technology was jettisoned on the release of Lion, Quicken stopped working on modern Macs. Fortunately, Quicken had enough haters prior to this that mature alternatives exist. For my needs, iBank was the best replacement.

Alternatives: I explored many replacements for Quicken when I moved to Lion. You might find others I examined fit your needs better.

iConquer

http://www.kavasoft.com/iConquer/

$13. A very sexy Risk game, somehow more addictive than the hordes of other Risk clones. It allows network play, but only 10 games before you have to pay for it. For the ambitious, developer tools are available to make custom maps and AI players.

iDraw

http://www.indeeo.com/idraw/

$25. Shortly after the dawn of the Mac came MacDraw, a program for editing vector graphics (where images are made up of editible primitive lines and shapes). I prefer using vector graphics when possible (as opposed to raster graphic tools like Photoshop, which edit a grid of colored pixels), as they scale better and are easier to change. I don’t know if iDraw was intended to be a ultra-modern evolution of MacDraw, but it feels like it in a lot of ways. It has a companion iPad app which feels even more so, with cloud syncing between them. One strike against it (in addition to the dumb name) is that you can’t try before you buy.

Alternatives: Not long ago, few options existed in this space other than the very expensive Adobe Illustrator, but now quite a few compete. Others include VectorDesigner (previously recommended, but now too expensive compared to iDraw), Artboard (a simpler user interface, not as powerful) and Inkscape (free, but clunky). Note also that some traditionally raster editors are starting to get very simple vector drawing features (such as Pixelmator, mentioned below).

iPhoto Library Manager

http://www.fatcatsoftware.com/iplm/

$20. If you ever need to merge two different iPhoto libraries into one or switch back and forth between multiple libraries, don’t even bother trying to do it yourself. It should be easy to do but, inexplicably, isn’t. Just pony up the cash for this program. You might also want to grab iPhoto Diet to remove some of the bloat iPhoto creates.

iTaskX

http://www.itaskx.com/

€80. Some switchers need a replacement for Microsoft Project, and for some time they didn’t have many choices. Now, however, dozens of possibilities exist. Since my previous recommendation in this space, Project X seems to have been abandoned, it appears that iTaskX is the current choice, as it matches Project’s feature set well and can even read Project files.

Alternatives: Some other possibilities in this space are OmniPlan, Merlin or, for something slightly different, Curio. A number of on-line only tools also exist now, such as Teamweek.

Leap

http://www.ironicsoftware.com/leap/

$26. Leap provides an alternate way of accessing, organizing and finding your files, making use of the OpenMeta standard to add tags to file metadata. Using any tags you care to add to a file, as well as other file metadata such as file type, modification date and so on, you can perform complex searches, either ignoring the rigid hierarchy of folders, or using it to augment the search. The “All My Files” view in the Finder (since Lion) implements a terrible and weak version of this concept, but Leap is a whole different level. Leap really shines if you have a lot of a certain kind of file (such as PDFs or video) and want to search for a specific one.

Life Balance

http://www.llamagraphics.com/

$40. A unique, cross-platform to-do manager with iOS synchronization (though still no iPad app). Their web site explains it better than I can. Takes a little getting used to, but is the best to-do system I’ve ever used. After a 30-day trial, save stops working unless you pay for it. There is also a Win32 version, if you’re into that sort of thing. Expensive, but unique.

Alternatives: LifeBalance is not constructed or intended as a GTD tool, though could probably be shoehorned for that purpose. Within the GTD space, Firetask seems to be the current darling, but Things and OmniFocus are mainstays. There are also a ton of “in the cloud checklist apps”, like Producteev, Wunderlist or even Evernote.

Little Snitch

http://www.obdev.at/products/littlesnitch/

$25. Brings up an alert any time your computer attempts to make a network connection to the outside world, allowing you to accept or deny the attempt. It can be trained to ignore things (like your web browser, chat client, etc.). It will only run for three hours at a time unless you pay for it. This is good enough for me, as I tend to run it only when installing new software. (Some software “phones home” to its creating company, transmitting who knows what.)

MacFamilyTree

http://www.syniumsoftware.com/macfamilytree/

$60. A bit pricy, but the best family tree software I’ve seen for the Mac, or any other platform. It’s charting and reporting is excellent, but the 3D “flythrough” options to the UI are more gimmicky than useful. Nothing can be saved until paid for. Data is easily imported (GEDCOM, with all the bells and whistles) and synced to the equally nice iOS version.

MediaLink

http://www.nullriver.com/products/medialink

$20. If you have a burning desire to view the media on your Mac (video, pictures, music) on your Playstation 3, this is the easiest way to do so. Totally seamless and easy to use.

Name Mangler

http://manytricks.com/namemangler/

$19. Allows you to do search and replace on filenames, including support for regular expressions. Sure, you could do similar things with the command line, but this is easier. Also shows you the results of changes before they are made.

OmniGraffle

http://www.omnigroup.com/applications/omnigraffle/

$100-$200. Switchers itching for something like Visio should look no further than the professional version of this app. It does some things a bit differently than Visio would, but generally “differently” here means “better”. Visio, notable as one of the few products whose interface radically improved once bought by Microsoft, could steal quite a few lessons from the guys at Omni. Current versions also sync with an iPad version, and contain a bunch of the layout code from Graphviz. A limit is placed on the number of nodes you can have in a file until this software is paid for.

Alternatives: The Omni Group tends to build really great products and charge way too much for them, but chooses products that no one else is building for the Mac. What usually winds up happening is that someone comes along to undercut them with a slightly-less-good version, for much, much less money. For example: Shapes (though it can’t use Visio files or export to SVG, and OmniGraffle Pro can). The Mac Graphviz port isn’t really the same kind of product (it is more about mathematical graphs), but can be used to create similar output more programatically.

Paperless

https://www.marinersoftware.com/products/paperless/

$50. You know that shoebox or file cabinet you have filled with old bank statements, bills, receipts, statements and so on? Would you like to replace that with an encrypted database of PDFs? How about if details were optically scanned from the PDF and populated into searchable database fields? Paperless can do all that. Most banks and credit card companies now offer digital statements these days, so you don’t even need to do any scanning (though the app supports that as well).

Pixelmator

http://www.pixelmator.com/

$15. If Adobe Photoshop breaks your bank, this image editor is a strong choice, delivering most of what the average user will need out of a raster editor in an elegant interface and much lower price.

Alternatives: There are tons of image editors out there. Some not as powerful, such as Seashore, Paintbrush, Acorn or ImageWell. Others are harder to use, such as GIMP. Still others are more specialized, such as Pixen.

Postbox

http://postbox-inc.com/

$10. Postbox is a powerful e-mail client which works a lot better for me than the Mail app that ships with OS X. Searching, for example, is more powerful, as are its filing rules. It also integrates with GMail, if desired, as well as with third party services like Dropbox or Evernote. You can download a 30-day free trial of this application.

Alternatives: E-mail clients tend to be a personal choice. Some other possibilities are Apple’s Mail; Mozilla Thunderbird, Mailplane and MailMate.

Scrivener

http://literatureandlatte.com/scrivener.php

$45. I don’t use this writing tool much, but I know people who bought a Mac specifically to use it (it has a Windows version now, though). It is a word-processor type application targeted specifically at writers of novels, screenplays, research papers and the like, with a number of organizational tools.

Snapz Pro X

http://www.ambrosiasw.com/utilities/snapzprox/

$69. The king daddy of Mac screen capture programs, with a long lineage. Capture full screens, windows, selections to multiple formats. Capture video. Basically flawless, with a well-deserved five mice rating. Snapz Pro X can be used for a limited time before requiring payment.

Sound Studio

http://felttip.com/ss/

$30. While there are number of sound editors available on the Mac, most of them were pretty bad last time I looked at them. Not this one, though. Sound Studio does more of what I need it to, particularly with some features specifically to ease the importing of audio tapes.

Alternatives: Other applications in this space are Audacity, Fission and Wavepad.

Steermouse

http://plentycom.jp/en/steermouse/

$20. The Mac is known for true plug and play support of all sorts of mice and other input devices, but sometimes the default support isn’t enough, particularly with unusual peripherals. This driver supports a wide variety of devices, and allows much more customization than mortal man was meant to use. It can be used for 30 days before requiring payment.

SousChef

http://acaciatreesoftware.com/

$30. If you happen to have an iMac in your kitchen, you might as well keep a recipe database on it, particularly one that can search multiple internet recipe sources by ingredient or other characteristics. Includes a “ten foot” mode, so you can read the recipe from across the room if you need to, and control the display with speech. Other apps could also learn a bit from how it handles importing via copy/paste of arbitrary blobs of recipe text into the various fields of the database. This app sometimes makes its way into various sale bundles.

TextMate

http://macromates.com/

€39. In a world with dozens of text editors for the Mac, this app left them all in the dust a long time ago. Highly customizable, this app supports a huge number of computer languaes, supports macros, can be used as an external editor for FTP programs (like Transmit, below) and even makes building custom syntax hilighters fairly painless.

Alternatives: Text editors tend to be more of a personal choice than other software, so BBEdit (or its more limited lightweight version), Smultron, SubEthaEdit, skEdit, jEdit, xPad or even Emacs compiled as a native app or a Mac-style Emacs may be more your speed.

Transmit

http://www.panic.com/transmit/

$15. The file-transfer protocol (FTP) client for the Mac (also supporting other protocols, like SFTP, Amazon S3, WebDAV, etc.). Let’s you right click on files in a remote server, and edit them with external editors, such as TextMate (see above). Pretty much perfect. Until paid for, sessions can only last for 10 minutes and “favorites” cannot be saved.

Unison

http://www.panic.com/unison/

$29. Before the world wide web, there was Usenet, a vast collection of newsgroups. Though web forums have stolen most of their thunder, newsgroups are still useful. Unison is one of the best newsreaders I’ve ever seen. To access Usenet, you need a provider. In many cases, the company providing you with internet access quietly offers a Usenet feed (usually a web search for your provider’s name and “Usenet” will lead you to instructions). Fully featured for 15 days, after which favorites are disabled and it can only be used for 10 minutes at a time.

Witch

http://www.petermaurer.de/nasi.php?section=witch

$14. OS X has a built-in feature (cmd-tab) to cycle between application, similar to alt-tabbing on Win32. This preference panel adds a more sophisticated version (wired to opt-tab by default) that lists active windows as well as applications.