i'm in the same boat as you though i ordered a 2,4ghz macbook an hour after the annoucement, im still not sure its the right choice. It wont be delivered for another 2 weeks, and im afraid i might end up cancelling the order and place a new one for the small mbp.
Wont be playing the same type of games as you, since im more to fps games, but might play some starcraft or even diablo when the new ones come out.
Anyone have any idea of how well the macbook will perform in counter-strike source, connected to an external display with a resolution of 1680*1050?
Have seen a video on youtube with a guy playing some Team fortress 2 on the macbook and it runs with fps from 30-60, but when your in the middle of the action i seems like its mostly around the 30fps, and what happens when it gets run at a higher resolution, wont the fps drop to like 10-15 then? (which is clearly too low)