Here's a tip. Rather, it's a recommendation. Don't get anything with Intel chipsets if you're in the market for a laptop with a sufficient gaming potential.
Last week, Macworld brought us some benchmarks including one set for Quake.
Today, they brought us additional numbers for Doom 3, UT, Call of Duty, and, of course, Quake. It's for the Macbooks but more specifically, it speaks about the engineering prowess of Nvidia and how it succumb to Steve Jobs' reality distortion force.
Anyway, if you just want the gist of it. Here it it. 9400M rocks. If you're looking for a notebook with aintegrated graphic processor, this is the one to get right now. As far as I know, it's available for only the Macbook right now but it'll trickle out for others eventually.
Look for the intepretations at On Apple for more.
Note: I have to say that the Mac system requirements does not translate directly over the PC. For example, Spore plays on the G945 but not on the Mac. And to be fair, XP systems (not sure about Vista) are better suited for gaming, generally coming in with better numbers.
Another Note: Barefeats as additional benchmarks waiting you. Go now!