I agree with Lex on the specs aspect. And most people would probably say Alienware.
I wouldn't recommend to anyone to buy a laptop for gaming, unless its free cell they want to play. I own an Alienware laptop and it does ok for gaming, except it tends to overheat easily. The reason I wouldn't buy again is its pointless, the purpose of owning a laptop is the portability, and my alienware is not portable at all. Add the fact that its ridiculously expensive compared to a desktop that performs at the same level.
If you want to game and you want a laptop, get a good desktop and buy a netbook.
p.s. If anyone wants an Alienware laptop, I'll sell mine for $600 obo, not even a year old.