I'm using it, Home Premium.
I just bought myself a new pc (C2D E6400, 8800GTX, 2GB ram) and I wanted to give it a whirl. So far its been as good as I've expected. I've had 3 BSOD, but I think they could be related to my video drivers, as the nVidad drivers are still beta.
The other reason I wanted to get it is because I'm a dev and I'm interested to see what Vista can/ can't do in terms of deving. Personally I think VS2005 looks fucking fantastic in Vista, it doesn't look like an app that was built for XP, it looks home in Vista.
I like gadgets, at lot of people wont, but I always used Samurize in the past, gadgets just mean I don't have to rely on a 3rd party software and I'm wanting to get cracking with making my own ones

Gaming has been fine, turns out PunkBuster doesn't play well with Vista, it insists that you run the game as administrator so PunkBuster can get full OS access and be sure you're not cheating.
Ironic you have to give it complete access to be sure you're not cheating...
All in all I'm loving it and would like to use it at work, but I don't think we're going to move to it for some time