Well obviously something still needs to be fixed if it's still having issues. It isn't Vista's fault...XP can and will end up the same way. Worse, actually, since Vista is much better at fixing itself.
If you must get rid of Vista, go for windows 7. XP is old, and nowhere near as secure or advanced as Vista or 7. What you want to do is roughly the equivalent of going back to win98 when XP SP2 was released.