Being a TechNet + subscriber I have had my hands on Vista (and Office) for a month or so (the retail version that is; not the beta's).
I must say it does run quite smoothly on my Core 2, 2GB ram, Ati X1900XT. Funny thing though: I have an internal card reader which does not seem to be recognised at all; no missing hardware in my devices list; but it simply does not work

And ofcourse; specially in the beginning lots of programs wouldn't work; think of Nero and McAfee etc....
But honestly; Vista looks very good; but what's new apart from the looks?