I would advise you to take something from Asus first and foremost, they have a good reputation in laptops, all my friends have an Asus too.
Asus has been making parts for many years for other brands and those parts are good too.
In 2007 they decided to make their own brand of computers and of course they could with their good parts.
Also I find most of the time ASUS products are more rugged.
Forget AlienCrap, really a rip off.
I am not saying the rest is shit and all that, but merely my own experience with ASUS.
It is a lot harder to advice on good laptops than it is on stationary. Also it is going to be hard to find a laptop that plays d3/wow on high settings for 600-700 dollars i think (unless the price is low as crap in the states, in sweden you'd get garbage for that amount).
I just did a google search for best gaming laptops 2012 and i got quite some results, might be worth doing and checking out the reviews and whatnot.