XP Pro myself, and apart from my initial cynicism and doubts, I think it performs really well. None of that fresh install palaver every coupla months like with WIN 98.
I note a lot of skepticism amongst WIN 2K users about WIN XP, mostly cos of the way it looks.
Thing is, most WIN 2K diehards don't realise XP is more or less the same OS but more stable, more capable of running old games and also capable of being displayed any which way you want, including a WIN 2K clone set up.
Bah! Luddites!
Linux? I'm playing with Mandrake 8.2 and am gradually realising that to understand this thing, you have to completely forget about Microsoft ways of operating. As good as Linux is, and all the enhanced GUI distros available, it's actually making me realise how user friendly Bill Gates' OS is. Oops, best duck....
Linux = steep learning curve.