Yeah, my SB5.1 won't work. Minimum is SB Audigy Value...and i suspect a lot more hardware won't work either.
Why don't u just buy the evaluation version and test it out before decide to buy or not.

In case u don't know, you can install VISTA WITHOUT the CD-Key (during install time) and it'll allow u 30 days access...more than enuff to test.
btw, IMO, the difference between ULTIMATE and Home Premium is pretty negligible. Unless you want to connect to a domain or something, Home Premium is just fine.
Other significant feature included in ULTIMATE:
(1) Bit locker - encrypt ur HDD....do u really need this?? Unless u r storing Goverment OSA like those toll agreement...why bother??
(2) Complete PC Backup - ala Acronis true Image or Norton Ghost. Probably a very basic and crummy imaging solution with limited function.(i read their backup system dun even have compression!!!). Just get a copy of Acronis 10 and you'll probably be much better off.
In otherwords, i think ULTIMATE is an absolute waste of money for the average home user with crappy software thrown in to justifiy the extra price.
I've already decided to buy it.. I just need a better soundcard and I need the proper driver for it..
And also, I agree with you on Ultimate, its just not worth it, since most of us are just using home computers.. but we'll miss ultimate extras like dreamscene and so on..