<< I've only used XP a few times, but from what I've gathered, it's just 2k with a lot of visual effects and annoying, unnecessary integration. I wasn't too thrilled with the GUI, so I think I'll pass. Maybe in a few years I might upgrade out of necessity, but until 2k becomes outdated, I'm sticking with it. >>
Well it's definitely a minor version update. Hence why it's version 5.1.
But it does have quite a few changes over Windows 2000. Mostly to do with new sets of policies, better hardware support, added network capabilities, etc. Nothing overly significant for most users.
It runs well on me so I run Windows XP on my workstation and 2000 on my server.