One final thing to be aware of is that most of the new computers come with Win 7 home edition and if you have a lot of XP programs like a scanner, Word processing programs, various utilities and programs, etc. you will probably not be able to use those unless you get Win 7 professional and download the XP system option. Even then there still might be some old XP programs that simply won't run under the XP option in Win 7. The two that were simply incompatible for me was my backup program - Acronis 9.0 and my external 24bit live Sound Blaster stuff.
Larry