Linux alternatives.
Once you’ve made the plunge to look at operating systems outside of the Microsoft realm, linux has typically been the easiest accessible. Lot’s of livecds are out there and much can be freely downloaded. Of course there is the Mac as well with Os X. I’ve liked what I have seen of it, but there is a higher cost of commiting to that platform. (Hardware +software). I’m also not comfortable giving up one company that has fairly tight control over the software for a company that has fairly tight control over the hardware and some of the software.
That much said, the roots of the Apple Macintosh OS X are in the BSD Unices. (Unixes?) Anyway, the BSD license is a bit different than the GPL of Linux land…. BSD licenses typically say (in a nutshell) you can use the code, just credit where you got it. You can close it, open it, that doesn’t matter as long as you CREDIT the source. For this reason you will find BSD code in most every modern operating system (yes even Microsoft’s Windows codebase has had some BSD roots.)
One of those variants of the BSD’s is FreeBSD and in this article, they present a comparison between FreeBSD and linux. There do seem to be some advantages over linux. The ports system (system for keeping track of and installing new software), has some features that seem to make it easier to track security vulnerabilities across the components of the system for one. There are some of the same desktop environments available for FreeBSD as Linux (KDE, Gnome, etc.) Since they both have unix roots there are a lot of similarities and a lot of software that runs on either platform.
There’s even a Livecd (freesbie), and a customization geared towards desktop use. PCBSD, this later one comes with a more polished installer and is geared towards the desktop applications more than the server side where FreeBSD is usually thought of.