For anyone who is interested in the the rather niche intersetcion of PC gaming and the Macbook Air, I have started posting a series of videos in which I actually test the MBA's ability to run various games. I'm far from the first, but I try to spend a little time looking at the effect different settings have on the performance and always keep Fraps running in the corner so you can see exactly what the framerate is (as well as how surprisingly low the framerate can go and still feel okay).
http://www.youtube.com/user/mediadesignspec?feature=mhum
http://www.youtube.com/user/mediadesignspec?feature=mhum