Hello everyone, I haven't posted in quite a while and now I'm back!
On topic, I voted Linux because I really like the fun of it especially distro's like Arch, Gentoo, or Slackware (though I also like Debian and Ubuntu for server usage and the large amount of stable packages).
However, I also have Windows available just so I retain compatibility because I might be getting a job this summer that would utilize ASP.NET. I really don't like it that much. It's basically unstable (which isn't necessarily bad, IMO), but since it's proprietary you have little control over fixing issues (which makes Arch and Gentoo a lot of fun for the Desktop).
More recently, I also got a MacBook Pro so I could use GarageBand but I ended up liking a lot of aspects of OS X. I think OS X is very stable and perfect for certain users, but for more of a power user like me, I slightly prefer Linux more, but not by much because of GarageBand (no recording software for Linux works as well in my opinion, though I do like the idea of JACK and all the programs that utilize it).
I think Ubuntu is going in the right direction for the desktop, however I've been testing Lucid and it's so well integrated it's almost like the perfect operating system and I think by it's release, it will be very usable for a lot of people that Karmic wouldn't have been usable for. I also like the new color scheme, because I got sick of the old orange/brown one.
It's good to be back.