They exist, and generally come in one of two flavors: applications that were originally born of X11 or the console and have been given a Cocoa makeover, and applications written from the ground up for the Mac. Let's take a look at some of the best, most useful free application software for Mac OS X.
The official OpenOffice.org suite can be run on Macs with X11 installed, but it lacks the Aqua look and feel. NeoOffice, on the other hand, is a customized version of OpenOffice.org that looks and feels like a native app. It uses the system fonts, plays nicely with the native print drivers, and lets you drag and drop text and data from and to other Mac applications. Plus, it has most of the features you'd expect from OpenOffice.org itself: importing and exporting of various kinds of Microsoft Office file types and a straightforward interface.
NeoOffice releases lag a bit behind OpenOffice.org releases. NeoOffice has also been maligned for its slowness. Yet it's free, stable, pretty, and about as good as you can do without paying Microsoft.
NeoOffice 2.0 Beta 3, which was released August 29, is quite polished and runs fine on my Intel Mac. It's a must-have for Mac hardware fanatics who've sacrificed their software budgets.
Anyone who's spent time ripping and encoding DVDs to MPEG-4 files on the command line will appreciate HandBrake, a glossy front end to a range of popular encoding and video manipulation libraries mostly from our friends in Linux land.
HandBrake is as easy to use as things like this get. You can encode DVDs or VIDEO_TS folders directly to a wide variety of open, compressed formats. Once you select a source medium, HandBrake decides which track you probably want to encode based on track size. You can also enter your own target file size if you're aiming to store the result on a CD-R or VCD.
HandBrake is also one of the easiest ways to rip your movie collection for viewing on an iPod Video. There aren't really any downsides to this software.
Though OS X comes with a decent Aqua text editor, it's a bit light for my taste. Although the classic Mac text editor is BBEdit, it's not free, and neither are alternatives like TextMate and skEdit.
This is where Smultron comes in. It's a solid piece of software with code/markup highlighting, split windows, tabs, regex searching, and even some bonus stuff, such as .Mac syncing that lets you save commands and "snippets" to your iDisk so your customizations work on any Internet-connected Mac running Smultron.
The only additional feature I'd like to see would be integrated SFTP support, which BBEdit and skEdit both offer. In the meantime, you can use Fugu, a separate but slick SFTP interface, to handle secure file transfer if you're not at one with the command line.
Want to run Windows or Linux on your Mac? For free? Without dual or triple booting? The easiest way to do it is probably with Q, a sleek Cocoa interface to the popular emulation software Qemu. Q provides the features of Qemu with the familiarity of the Virtual PC interface. With Q, you can run various versions of Windows, Linux, and any number of other operating systems on your Mac, inside OS X.
Q doesn't have a virtualizer, unlike a similar but commercial program, Parallels, so even native code is still emulated. This means that even on the fastest Intel Macs now available, emulated guest OSes will run like they're on a 500MHz machine.
What it lacks in virtualization Q makes up for in cost. It's a great way to experiment with alternative OSes safely, or run older Windows software you might be stuck using.
What mIRC is to Windows, Colloquy is to the Mac. Sure, the *nix world brings plenty of powerful IRC clients to the Mac, with the most notable graphical client being perhaps X-Chat Aqua. Colloquy trumps it, though.
Colloquy is stable, well-organized, and customizable. It's uncluttered enough for a beginner to find it usable from the start. However, it also provides a full range of IRC client functionality, from custom styles to file transfers to automatic login to bonus stuff like an AppleScript dictionary. The interface pulls out all the stops Cocoa-wise, and the application is regularly updated.
Colloquy is an unusual open source application in that it is arguably the best applications of its kind for the Mac, free or otherwise.
As the Mac open source community continues to evolve, so will the software it produces. The future of quality, free, open source native Mac software is bright. Enjoy it!