Bah, the PC Nazi's are idiots anyways.
The big downside is that for a good gaming laptop you end up paying at least twice what a desktop is going to run you. So look at paying at least $1500, if not quite a bit more.
What you want is a decent processor (dual core, 2.1ghz) and at least 3 gig of ram (which means yur gonna be running Vista, 4 is going to be better for you). Look for a laptop that is using either an ATI or an nVidia chipset (not an intel or some other type) for the video, and has _dedicated_ ram for the card. Your sound won't matter too much, if you really need better sound pick up an external USB soundcard or something.
Gateway makes reliable laptops, as does HP. Dell seems to have partnered with Alienware, and those are some pretty nice gamer laptops. The Lenova laptops seem pretty reliable also.
Okay, so here are the problems with a gaming laptop:
*Small screen (usually you get a 15 - 17" screen, but they are good screens)
*Heat (laptops get very hot, so playing for a long time could be a bad thing)
*Control (you will need to buy an external mouse, period. Trackpads are worthless for gaming)
*Longivity (gaming laptops seem to have lower battery life, probably because they have more power than a normal laptop)
*Repairs (you can't repair a laptop yourself generally. Should _anything_ break you are without a PC for awhile)
Now the gaming laptops are not too bad for portability really, what with how nicely things are getting condensed. Basically check one of the major manufacturers and see what they have under gaming laptop. 6 to 15 pounds isn't too bad.. I take my desktop machine to PAX every year.. the first year it was still in a big heavy full tower case and weighed in, just for the main box, at close to 60 pounds.