Dell Vostro's have good value even without coupons. They offer GT series 8400M and 8600M cards for $100 or $200 extra. The only downside to getting a Dell is that they sometimes ship with grainy screens. But they are the cheapest notebook you will be able to configure with nice graphics.
Occasionally, HP will run 30% off $999 or more (this offer ended a few days ago, but it might come back soon). So you could build a fairly nice system at a good price. Downside to HP is that they only offer GS series 8400M and 8600M cards. Gamers usually look for GT's since they perform much better. But build quality, looks, and overall value is excellent in HP notebooks.
Lenovo ThinkPads are occasionally cheap with 15% coupons they regularly offer. But generally, they cost a bit more since you are usually paying for workstation grade graphics if you want to configure a gaming laptop.