Almost five years ago I took this test, and it classified me as Amiga OS - now I took the same test again and came up as OS X. It would be interesting to see what has changed in more detail; I couldn't figure out any questions that I definitely would have answered differently five years ago.
What has changed in the last five years, however, is that run OS X on most of my computers. Back then, I had Windows 2000 on my desktop computer (with coLinux for development), and Windows XP (I think) on my laptop. I do have a W2K VM on my home Mac (mostly used for getting dissapointed at SF Anytime, a local video-on-demand service that requires Windows (and lately, newer Windows than Windows 2000)), and at work I keep a spare hard disk that I plug in when I need to do things that requires Windows (some of the bureaucracy tools require IE, among other this), but about 80% if my time is spent in OS X and 19% in Linux (although it depends on how you count; I'm pretty much always logged-in to my home Linux server (a small fanless VIA x86 with a flash disk), for example, and similarly always using a handful of Linux servers at work where, among other things, our testing infrastructure is largely Linux- based, even the parts that runs automated tests on Mac OS X (which in itself is an interesting topic for another talk or blog post).