Thinkton,
I would suggest looking around before you go with "AlienWare," while nice, but waaaaay overpriced, IMO.
Plus, we need to know a little bit type of games you wanna play, and that might help us out a little bit more. Hardcore? Mid to light? Gotta tell us! =D Plus, how long do you want this Notebook to last?
If your in for the hardcore gaming, I still suggest staying to desktop, it's tons cheaper, and easier to upgrade while being more powerful. But I digress.
Keep in mind, dual core (Quad is useless for the most part since games don't even almost even use dual cores) is most likely way to go with about 4 Gig's for RAM and go with x64 so uses all your RAM and 32 bit will only use 3.2 to 3.5 of your 4 Gig's of RAM) plus x64 is more stable.
Also, make sure you have a good video card, and do research on it for some are plagued with bad drivers, bad temps, or just other general defects. I also suggest this in general for what notebook you can. You wanna plunk down the change, research, research, and I can't say enough!
Some names to look at...
Dell (Make Alienware too, but their XPS line is good from what I hear)
Sager
Asus
G'Luck,
Ali