An old argument that is becoming stale.
Yes Vista takes more resources, therefore 2 or more gigs of RAM is best. Also the videocard needs to above medium speed.
I run Vista on an i7 940 processor, through a GeForce 280 card with 3x2 gig of fast 1066 RAM.
To slow things down I use Matrox Triplehead2Go.
And my favourite game is Flightsimulator X which has a massive scenery rendering task which is compounded when using an aircraft with a complex VC and also in real (and heavy) weather operations.
XP, who needs it?
So satisfied am I with Vista, that I am not going to look at Windows 7 until it is RTM. It is freely available in beta at the moment, but I can't be bothered.
As to the fuss over Administrator control popups, UAC can be turned off in seconds. So can Windows Defender if you are running a third party firewall and antiviral etc programme. Aero should be turned off in the first few seconds after installation.