If you are going to up-grade to vista. May I suggest that you run the compatable test first.
You might need to install a new vidio card.
Anothe problem I've run into if you have a scanner does the mfg. offer updated drivers. The same with your printer. When XP came out it took HP for one, 4 months to offer up-dated drivers. This time they state for quite a few printers & scanners sorry your product is too old & we will not be offering updates.
Plus if you duel boot which is fine except everytime you boot into XP Vista will deleate all the System restore points it has created.
I'd suggest reading a lot more posts here as to problems encountered by others & give suppliers a chance to offer up-dates to printers & scanners & other programs you might want to use.
I am considering upgrading XP to home premium and it was suggested installing vista in a second partition giving a choice of OS when booting up. Is this the consensus of others who have upgraded and once everything is working as it should do you just delete the original XP partition?