I called MS for support. I think it was in 2006. I purchased a copy of XP x64.
Spell check did'nt work in OutLook Express. I talked to several people for hours. The first problem was that none of them spoke english very well. The second problem was that after all that time they didnt have a clue as to what was happening. I find out later that because the way MS wrote XP x64 you can not get spell check in outlook express. You have to do a work around. Dont you think they would have know that? What a waste of time.
I got side tracked..
Here are the different versions of Vista. Personally I dont need Ultimate. Home Premimun has everything I need. You will have to make your own decision as to which one you need. http://www.microsoft.com/windows/windows-vista/compare-editions/default.aspx