Neal, if you can get one cheap, upgrade to Win7. I was a fan of XP for a long time,
especially when Vista came out and I heard the crap about it, I was sceptical
about Win7. Then, I upgraded my system with more RAM and a better CPU.
Switched to Win7 64bit and wow, I could never go back to XP now. I fiddle around
a lot with 3D stuff and video effects and Win7 programs being able to use that
full 12GB of RAM I got is just fantastic.
Of course, if you're not a big gamer/3D artist/Video thingamaling, then XP is good, for now, but when the time is to go up, go with Win7.
(unless Win9 is out by then, which by following the WinXP-Win8 windows' is probably better than Win7

)