the only reason I have a windows system is because I need it for working on windows software (pretty hard to work on a patch for winmx using only wine for example...) and then only my workstation has it on
I used to use windows 2000, and flat refused to ever touch XP - and have never been forced to use it, never do use it... it stays within vmware
I now use windows 2003, purely because it is faster booting than 2000 - it takes long enough to reboot without the extra delay of 2000... lol
Also judging by what I've seen so far (and going by the assumption that everything they messed up in XP they seem to be continuing down that road... just look at XP SP2!) I think I can safely say that I will never use vista on any of my systems either (except inside vmware where extra bug finding is done on every OS)