I believe the hard part here is that when it comes to laptops, not many have the ability to use a dedicated videocard, most have it built in. Now the chipsets they use will vary. Intel chipset is very compatible, but not known for its performance, which is something you want for your gaming. I think your going to want to find a laptop with an ATI, or Nvidia chipset for video adapter, the ATI Radeon 3100 you mentioned earlier probably isnt that bad, but again the problem is, laptop video adapters are built by each laptop manufacturer. You cant go and buy an ATI Radeon 3100 videocard for your PC (at least I doubt it). I run the game on ATI Radeon cards on both my PCs (x1950s) not laptops, but I believe the ATI chipset im using is OLDER than that 3100 that was mentioned, and I have no problems. Stick with a name brand chipset like ATI (Radeon) or NVIDIA (dont know thier chips). Try to avoid "shared" memory for video. If you do, then try to get as much ram in the laptop as possible so sharing that ram wont be a detriment.
Heed the information about running Vista that was previously mentioned as well. I am not a Vista user, but know it uses more memory than XP does, and despite MS's claims I do not think it manages it quite as well. Typical MS tradition, their next OS release will probably be top notch
