I would recommend you to stick to Xp for atleast untill Vista goes final for regular users i.e. January 30, 2007.
@Womble
Ehh, To my current knowledge, then Vista final is only legally available for some volume license customers, MSDN or TechNet subscripers
Are you recommending him to use pirated software or are you simply suspecting him to be in one of the above mentioned groups ?