yep, i'd suggest getting a lappie with a good pre-installed card coz it seems hard enuff to upgrade a desktop card, with all the overheating issues and all, but a laptop, forget about it!
also, would you want the lappie on the road or do you have an outlet to plut it into? coz battery life is a huge issue, i would imagine that the more powerful the game is the better the battery runs out.