Alvo,
I'd go to Dell's site, and look for an Inspiron or XPS notebook build with NVIDIA GeForce 8600M GT card. On a scale of 1 to 6 with 1 being highest performance, that is a tier 2 card, and it supports DirectX 10, which is the next generation for gaming. It won't run all the latest games at their highest settings but for the price range, it will be good for most games, with nice detail levels. The Nvidia GeForce 8800 series are top notch gamer's notebook video cards, but you really pay for it (they are usually in the $2K+ range notebooks), and they run hot, so it will probably only be an option for large notebooks that can allow sufficient cooling.
For other factors, also look for an Intel Core2 Duo at 2.0 GHz minimum (don't bother with anything less than 2.0 GHz in a Core2 Duo, you don't get the performance boost on the dual core below that level) or a similar AMD dual core processor. (If you are planning to go with wireless for your primary notebook network connection, I would go for an Intel processor with Centrino technology. It makes a big difference in wireless connection range and stability), and 2GB of RAM. If you can find a 7200 RPM SATA drive, that is best but 5400 RPM is OK for a laptop, and reduces the cost. Look for at least an 80GB drive.
Just an FYI: Dell Outlet computers come with the same warranty as new, and they are already built so there is no wait. I have purchased 3 computers from the Dell Outlet for personal use in the last 5 years, and more than a dozen for business use, and have been very happy with them. My current notebook comp is an Inspiron E1505 with XP Media Center edition, which I purchased for under $800 on the Dell outlet. The video card in mine is a tier 3, and does OK with WoW on middle settings. The Nvidia card I mentioned is a notch above it, and suitable for most gaming.
You can get a good notebook computer with the NVIDIA GeForce 8600M GT card and the other things I mentioned, from between $1,000 and $1,200 probably. I checked the Dell outlet's current inventory, and there was at least 1 notebook with that card and the other things, for less than $1K.
-Skylark