I sure hope you are going to put Vista 64 on! Other than the normal cautions that
you should be accustomed to, I have included the MS site below for you to look over.
Vista will not just do an upgrade of XP and include everything, but it does a reasonable
job of things considering what we have had to do in the past to put on a new OS.
http://technet2.microsoft.com/WindowsVista/en/library/1a3fbe72-9de8-4b94-b254-586a61843a041033.mspx?mfr=true