The main problem of Vista to me is that it is so bogged down with unnecesary extras when you first install it. There are like 2 kinds of notepads, tablet PC stuff, and a bunch of other ridiculous things. I also hate vista becase whenever you want to upgrade to it or downgrade from it, the drivers are really hard to find and often I have to search hours for single driver programs. Not only that, but Vista took forever to boot up. My 333mhz computer with windows XP booted up faster than my 2.4ghz computer with vista.
If you think that UAC is annoying, you can turn it off you know. Just go to control panel, then and type in "UAC" into the search box. You'll see a link for "Turn User Account Control (UAC) on or off. Then uncheck the box with Use User Account Control (UAC) an click okay and then reboot.