For those who are wondering - TurboTax 2006 installed and updated without a hitch, reading my old taxes with no errors or any warning messages at all.
I expect the 2007 do the same, which is a great news to me!
I haven't booted to XP in over 2 weeks, and if I don't have to use it, I won't.
So far extremely pleased with Vista Ultimate x64. :thumbsup: