After my XP disappeared on me, don't ask, i went to Vista seeing as in near future in my opinion many new games will be only be able to be play on vista and that many useful programs will need Vista. From the week or so i have used it, some programs aren't usable. But most are. I have only two...three programs max not be usable. Yes, XP has little to no problems when it comes to compatibility and the such, as of right now. But as more games and programs come out, they will require Vista and you will be stuck with your copy of Xp that you spent X bucks on that could of bought Vista.
Yes, when it comes to games, hardware, programs and the such, some encounter problems with Vista. But with the numerous Vista users out there who write on forums like this one, who have spent the vigorous hours fixing these problems, you don't have to. Simply search forums or google problems, and most if not almost all of them will have instructions to fix them. But most of them just require new drivers.
So in the end, if something doesn't work, yes you may have to do a little work to fix it. But in the end and the future, you will be glad to have Vista on your rig.