Vista > XP
I didn't read all 100+ comments but seems like everyone hates vista
I have it on my comp at home and couldn't be happier. i do have an amd dual core 3gig with 2gig ram. But i'va had NOT ONE PROBLEM since i installed it.
I actually installed XP before i installed vista so i could compare the 2 OS and vista won everything i tested for.
It starts up faster
once your logged in, programs take far less time to load. (xp takes forever once you login to load the startup stuff, vista doesn't)
shutdown time was faster
I also ran 3d mark from www.madonion.com and had a significantly higher mark (just for changing to vista). I couldn't compare the general pc side as they have one for vista and one for xp.
Exactly the same hardware and vista won. Seems like the problem isn't vista, just your asking a cat to pull a carridge instead of a horse. Was this any different from when XP came out and everyone complained about having to upgrade from 98/2000? In a years time when hardware prces drop, people will be happy with vista. only paid about $230AU for my CPU not exacltly expensive.
If your machine isn't upto running vista, you shouldn't be running it. Also if it's a work machine with bad graphic capabilities, turn down all the flashy stuff.
In short, i've tested xp and vista on the same hardware and VISTA WAS BETTER, not on average but everything i could find to test them with.