I've had Vista on my 2yo desktop from new, and it is perfectly fine. Problems may occur when you install it on an older machine, as compatibility is not always good, even if they say so.
Some older programs may not work as well, either, so you need to update them.
My daughter resisted Vista and stayed with XP, but when the laptop started to playup she bought a new Sony with Vista, and is very happy with it, none of the problems she expected.
You always hear the bad things, but the good ones aren't news.
That said, Windows 7 seems to be what Vista should have been, so why not wait for it?