I say go with XP 32-bit, I used to use vista for the dx 10, but I was seriously having a ~50 fps drop in all of my games, and it was horrible and slow and bloated. I use XP now, and my computer is waaaaay faster. XP is much lighter weight, and its worth not being able to play the few dx 10 only games. And there are patches available for a lot of dx 10 games that will let them be played on dx 9.