At the CNET Labs, Snow Leopard beat Windows 7 hands down in every category except, guess what? Gaming.That’s right, gaming.
Yes, only gaming, and gaming to me is important, and it must be to you, too. The tests were conducted in the Macbook Pro, right now the only computer that officially supports both operating systems. In the gaming test, Windows 7 got 5 frames more than Snow Leopard did.

And one thing that probably is very important to the average user is: battery life. And boy, did Windows 7 get scorched:

Note the tester said that the poor battery life of Windows 7 was due to bad drivers, so maybe we can spare Windows on this one until better drivers come out.
So basically, Windows 7 is still behind, but on a Mac. Now the showdown of the century would be a Windows machine vs. Macbook Pro.
[CNET]