Yes, I run an 8800GTS 512 card, and was running 178 series drivers in each OS (though a different version is provided by nVidia for Win7).
I did see a few fps less in win 7 vs vista, but keep in mind that we are talking about 2.6% average fps decrease.
I've added system specs to that post (at the end).
FSX saw a 7.8% performance loss at Medium-High settings, and pretty much no loss at Ultra High settings. My usual settings are in between, so I see about 3 fps less than usual by running 7 vs XP.
Black Shark had crazy GAINS in performance, minimum fps increased by more than a factor of 4, average fps were nearly doubled.
So for the imperceptible loss in IL-2, the nearly imperceptible loss in FSX, and major gains in Black Shark, I'd give it a thumbs up!
That says nothing about the desktop user experience which is certainly much better than XP, and reportedly a bit better than Vista. I wouldnt so much blame the OS for any hits, it actually appears to handle resources with much more intelligence than XP does - the apps you run just have to allow it to do that!
[edit] Here are the other benchmarks I've run with Win 7 vs XP - Nothing fancy, but quick and dirty and get's the job done:
http://www.txsquadron.com/forum/index.php?topic=2675.0