If only they haden't messed up the sound
I played around with various Vista releases and had a lot of problems with them.
Since before Vista's official release, I've been installing Vista then reverting back to XP on a monthly basis, trying out the latest Vista drivers, finding them useless, reverting back to XP for another few weeks then giving it another go. Each time the Vista install has got better and better driver support until it's got to the point when it's only the sound that lets me down.
The biggest let down is Creative with their almost "couldn't give a dam about the user" attitude towards their customers. Yes they finally have drivers that give some sort of sound, but their software support is awful. If you have the latest X-FI, then no worries you still get surround sound with your games such as WOW (but still don't get a full software package), but if you foolishly brought an Audigy 4 a few months ago then you are stuck. No surround sound yet. Yes I know MS altered the way sound was done, but Creative now want to charge Audigy owners for their "Alchemy" software when it's finally released.
I brought (built) a new PC a couple of weeks ago along with a non Creative "Auzen X-Meridian" sound card and also purchased Windows Vista Premium 64bit.
Every bit of hardware I have works 100% fine on it. Full support for my sound card, my Saitek X-45 Joystick, my Zboard gaming keyboard, my CH Products pedals etc, even my Trust Graphics tablet has 64bit (working) beta drivers out for it.
Compared to a couple of months ago I would say driver problems have improved greatly.
UAC hasn't been a big problem for me and I haven't turned it off. My Zboard, sound card, anti virus (avast) etc all start up at boot time without any problems. I have one program (Everest Ultimate) that I have to click on "Windows needs your permission to continue" a couple of times during login and that's it. If I run certain system commands, say "Start, Administrative tools, services" then I have to click on an "OK" button but it's no real hassle at all. The one thing I did do was create a separate C:/Games directory so that I can play around with my flight sim and Oblivion mods to my hearts content without UAC hassling me.
The biggest complaint I see is with people saying that Vista is a resource hog. People cant seem to grasp that Vista is designed differently from previous windows versions. With XP, you wanted as much available memory to run your programs as possible. With Vista, it PURPOSELY uses as much available memory as it can, and then releases it if it's needed to run a game or whatever.
I do like Vista, it works superbly for me. If I had a different selection of hardware and there weren't drivers available then that wouldn't be the case, but as said, all works fine for me.
Would I recommend anyone upgrade to it? Unless they need to play Halo 2 (or other DX10 games when they become available) then absolutely not. Why not? Well there's no real point. On my old PC I ran XP, it ran well. I ran Vista, it also ran well. But both ran my programs (except for the lack of surround sound in Vista) perfectly and in my honest opinion there's absolutely no point in ditching XP and forking out the money for Vista.
I also would not recommend upgrading XP to Vista, if you do want to move to Vista, reformat.
That said, if your buying a new PC, would I recommend you buying Vista, Absolutely. No reason I can see for sticking with XP.
So to sum up, I'm happy with Vista 64 Premium. I think there's a lot of "Lets have a go at MS for the sake of it" and "Vista's crap, a mate down the pub said so" attitude around. I think the driver support from 3rd party vendors has come on in leaps and bounds. I wish MS hadn't got rid of the Directsound 3D hardware acceleration support, but hopefully newer games should get round that problem.
I would like to add that I'm no MS liker or hater. I have for many years (and continue to do so) dual booted running various versions of Linux such as Gentoo or Slackware .
PS, Just in case you didn't get it, I think Creative Labs customer support is crap.