We just need a virtualiser (emulator?) that Vista isn't aware of when installed ... if that's possible. Vista Home does reek of Crippleware though, given that all of Ultimate's features are on the DVD ...
I will probably buy Ultimate, since it'll be my first bought OS since Win98 ... well, I also bought XP Tablet with my tablet, I guess.
Frankly I think they should reward buyers of Ultimate with the ability to install on 2 or 3 machines - enthusiasts will often have a few machines at home... or at least, there should be a cheap option for adding a 2nd or 3rd licence ... but then I guess folks would share it with their neighbours...