Rajaie, you are smart! Windows Vista still contains a lot of bugs currently and I think it will take a while for Microsoft to remove them. That being said, I am with XP!
I am using XP, and I don't see any reason changing my OS to vista XP is better to me and I heard many rumors that there are a lot of problems in Vista in gaming and I hate that because I am A Computer game maniac.
I'm using Vista, but my other HDD is XP. I switched to Vista being my main around a week or two ago, and it's working nicely.