3 systems I have had running on Vista with no real problems over the last few months.
P4 3.06
Abit AI7 mobo
Nvidia 6800GS
2gb ram
Creative X-Fi XtremeMusic
AMD Atlon 3500+
MSI sumthing sumthing board
Nvidia 6800GT - ATI X850XT
2gb Ram
Creative X-Fi XtremeMusic
C2D E6600
Gigabyte GA-965P-DS3
Nvidia 7950GT- ATI X850XT
2GB ram
Creative X-Fi XtremeMusic
On all builds I have used 64bit Ultimate, the biggest problem was with Creative. For the longest time they had no workable drivers, and when they finally released some they came with expirary dates (who the hell does that?). Now everything runs fine, I play games no problem and the sound is working pretty good. Though Creative is complaining about Vista and EAX does not work, nor will it anytime soon. I have had problems now and then with video drivers, some would work on 1 system, but not another, or certain systems would have glitches, but nothing universal.
All in all everything has been what a Beta should be. I have used it to trouble shoot my systems and taken what I have learned and applied it to my work.