Vista is nowhere near as bad as it was at launch. Service Pack 1 fixed a lot of issues, regular patches have helped with others, and still more "problems" were the result of bad pr and perception rather than any real failing.
Even UAC isn't as bad as you may have heard. The trick there is to just put it up with it for the first month maybe two, during your personal "burn in" period with your computer. During this time you're installing and configuring lot of new software, changing a lot user and system settings, and in general just playing around. So of course you see a lot of prompts here. This is exactly what happened with all those reviews you saw online saying how bad UAC is: they were still in the burn in period for the operating system.
After about a month two things happen:
1. You don't see as many prompts, because you're not making as many system changes.
2. You get used to them, so that prompts that remain actually make sense.