The lights are on
I've had no problems running games on Windows 7 x64 since the RTM was released. I've run UT3, MLB 2K9, The Withcher, GTA IV, HL2, Devil May Cry 4 and a few others with no issues, so far.
I liked Vista for what it was but if you didn't have the hardware it just wasn't worth it. With Windows 7 it runs fine on my laptop with a Celeron CPU @1.7Ghz and 2GB RAM.