You might gain some extra features for filtering and rules, and intergration of MSN messenger with Outlook 2002 (XP). Some of the features are only valuable if you are using Exchange 2000/2003. OfficeXP intoduce smart tags (Which are annoying to me), and some other things which I don't even know how to use (I'm not an avid office user, I only use word, excel, and outlook). Even though you say money is not a concern, I still don't think it's worth it. But that's just my opinon.