I'm not sure what that system is going to set you back, but if you're into gaming you should really be looking at the Gateway system with the 8800 GTS in it... it's just a bit over $1200 I think and that's DOUBLE the GPU muscle... 8800 GTS = Two 8600 GT.
i think the GTS would be able to give a bit more performance than 2 8600GT's! but seriously, the 8600 is not good for gaming. it's barely faster than the 7600GT. it seems to me like you're looking at the dell 17 inch inspiron. dell doesn't offer anything reasonably priced that can play games (in laptops at least). as rodney said, look into a gateway.