This past weekend, I wiped my laptop and main machine clean at home and installed the final version of Vista, available from MSDN if you have a subscription.
I'm loving it so far, but I ran into some hard drive problems along the way.. namely one of my hard drives dying in the middle of installing iTunes. Joy! Not Vista's fault, though.
Anyway, Vista's start menu is completely different from XP, and by default always shows the top used applications. You have to click "All Programs" to see your full start menu. And the view then switches to a single scrolling list, with folders that expand inside this list. What's been driving me crazy is that clicking/hovering to open the start menu folders takes seconds. CPU usage goes to 100%, and the start menu becomes sluggish while this happens. Then the folder opens. Unacceptable.
I did a search on Google, and funny enough, people have been having this problem since early betas of Vista. It's crazy that it hasn't been fixed in the final, but here's hoping Microsoft releases some quick fix later on, and preferably before the January public release, hrm?
In the meantime, like that forum post suggests, if you go into your start menu options and turn off the highlighting of new programs, it solves the problem. I'm guessing that Vista is trying to look up the "last modified date" of every start menu item on the fly, and that's causing the delay?