Hi all -
Dave Vronay here! I am a research manager at Microsoft, running a team called the Windows User Experience Compliance team. We make the UI guidelines for Vista - check them out:
http://msdn.microsoft.com/windowsvista/uxguide
The other big thing that we do for Vista is drive Fit & Finish. Fit & Finish is really getting a big push for Vista, with lots of people spending time tracking down the minor errors and glitches that haven't historically been "ship-stopping" but certainly contribute to a feeling that things are not polished.
YOU can actually participate in this process by providing your feedback on the various pre-release versions of Vista we are putting out. My team and I are always monitoring web sites, blogs, discussion lists, and anything else we can find to make sure we are putting the polish where it is going to have the biggest impact.
I really you try Vista and let us know what you think of our effort so far!
- davevr