I agree with the need for a Vista Service Pack, or in lieu thereof, at least release upgrades for enhancements like this.
I actually have UAC turned off on my desktop, since the purchase of my notebook as I now use it for almost everything. The desktop is used for "obtaining" my TV shows in digital HDTV format, manipulating video files and playing Titan Quest. I have had no attacks or anything come in through the net or introduced elsewhere. Then again, I do not open unknown attachments to emails and I run Avast and Windows Defender.
I have UAC enabled on my Notebook, and I really do not like the hassles, but I put up with them for the added security as it is my main system now.