Problem with Dell laptops is often the portability factor. The lighter ones have much less power. Gateways, in my opinion, are better designed, but are definetly more expensive.
If you've definetly decided on an Intel CPU you probably should consider whether you want a Centrino or a Pentium.
I have heard mixed feelings about the Centrino. It is definetly better for the extremely portable machine, but I have also heard from an owner that despite its processing optimizations, it is simply not as fast as a Pentium...which seems to imply that if you want a gaming laptop, you should still lean towards the P4.
If you are probably going to get a Dell machine, my brother recently purchased an Inspiron 5150. Nice machine. On the heavy and bulky side, but it features a P4 (desktop version) clocked at 3.06 GHz and the machine still seems to keep an incredible 4 hours of battery life (I really don't understand it). On the Centrino side of things they have the Inspiron 8600 with a widescreen display.
Whatever you get, I would highly recommend at least 512 MB of RAM, and a 64 MB Graphics card (NVIDIA or ATI). Oh...and one more thing. Dell's support is not what they used to be. My brother's machine was shipped with a defective WiFi card, and they bounced him around from department to department and call to call just to "make sure" the thing was actually broken. After 6 weeks and many, many calls, (and long, long hours of waiting on hold) they finally agree to send a new one.