I think there is no point in upgrading at all. If your a gamer then it is worth upgrading because some games will soon be vista only, but if it wasn't for that i would just be with XP.
Heck if there was more support for Linux i could gurantee Linux would have a larger share in the marketplace (mainly because it is free), it's only becuase of the lack of compatability that it fails.
Fanboy.