id recommend the alienware 5790. Alienware: Area-51 m5790 Notebook - Learn More!
I got 2 gigs of memory in mine, and a 7200 core 2 duo. kicks serious ***. Battery life doesnt change wether your gaming or not. If im playing a game I get about an hour and 20 minutes. Same goes for desktop applications. Its not heavy to me, only weighs like 7 pounds. Huge bright moniter with an awesome picture. After buying this and knowing how it is I would have no problems doing it all over again. If you carry it around with you just get a backpack to put it in. I put mine if a backpack and go everywere with it. Even when I go riding my motorcycle. Id highly recommend it. I have not one complaint except for the alienware crap they first install on it. I formatted mine once I got it and used windows to connect to the wireless internet and got rid of all the alienware programs. Other then that flawless