Just got round to installing Win7 on the test rig and I have to say that first impressions are much like everyone else's, seems much much quicker than my Vista installation, more snappy like XP, no more of the hideous UAC pestering the crap out of me, but I did find one oddity tonight when I was setting it up and that was Firefox.
I downloaded the Firefox exe file to the desktop and double clicked it....waited....waited...waited...

...dou ble clicked again, waited....waited....still nothing apart from the
DVD drive spinning up. I ran it as admin and it worked first time, and then so did the other six instances that I'd launched
Cosmetically, I really like it with the exception of the quick launch icons, they seem too big and it's going to take some getting used to the show desktop control being on the right, I've had that in the quick launch bar since 2000bc
Very nice though so far.