Here what a friend advised about vista.
Be Carefull what type you get.
Vista basic has no aero-glass interface and is crappy, missing most of the nice features of Vista. Buy this only if you get your PC's from Tiny.
Vista Home Premium is better, but if you use your PC for any work at all, you're gonna be stuck when your whole company's on Vista and you can't log onto their network using the features only available in Vista Business
Vista Business has no media centre stuff, meaning its crap except for boring work.
Vista Ultmate is t3h shizzn!t, but costs a bomb.
Also, beware of licencing. If you buy an OEM licence at vastly reduced price (I've seen OEM Vista Ultimate for 100 quid on overclockers.co.uk), you can only install it ONCE, and can't upgrade AT ALL (restricted by over-zealous activation)
Go for the full licence or XP upgrade licence and you can reinstall as many times as you like, upgrade, even move the licence from one computer to another. You will still have to activate each time you do this :@
Also note that unless you have 2GB RAM, Vista spends all its time paging to hard-disc. lol, microsoft...