OS X is certainly the best thing to happen to Apple in years. To hell w/the freakin' iPod, OS X has revolutionized the only thing proprietary to Apple besides its hardware, & has certainly kept it afloat when nay-sayers would've had them sinking long ago.</soapbox> Anywho, with all that functionality built into an OS, there are still tons of users out there barely scratching the surface, & this article is a great start for anyone looking to delve a bit deeper...

"Based on the open source XFree86 project, X11 for Mac OS X is compatible, fast, and fully integrated with Mac OS X. It includes the full X11R6.6 technology including an X11 window server, Quartz window manager, libraries, and basic utilities such as xterm. Whether a Unix user or an X11 developer (or both), Mac OS X offers a platform where your applications can run without modification."