As readers of this blog may know, I'm not enamoured with Vista's UAC feature. I'm sure I'm not along judging from other web posts. In disgust, I filed a bug (titled "UAC Utterly Sucks") and it has just been closed. It was closed "BY DESIGN".
That's right, MS actually designed UAC to be this bad. The bug was closed with apologies for invoncenience caused, and offered a workaround to login as admin. Actually, this is not a great workaround - a much better way to deal with UAC is to just turn off the service using MSConfig.
So when you spend the rest of your life hitting the "yes" just remember that MS designed your experience to be this poor.