games are fine. no problem.
the ati drivers used to be a crappy, unstable hack job when they first came out. it would crash if you had a framebuffer console and x running at the same time and switched between them, as well as other problems. (i can't tell you for sure - never used them) but they have been getting better as ati releases new versions - they are fixing the problems, and not sitting on them for six months as one would expect. (ati is known for slow driver support, even in windows) actually, they're good enough that i'm thinking of giving them or the firegl drivers a shot, to see what they're like.
if you don't want to worry about overheating, then you may want to use acpi to throttle the processor down a little, maybe to 75%. it's slightly slower, but it doesn't get hot at all. i wrote a script that lets me easily switch throttling levels - i keep it at 75% when i'm doing normal desktop stuff and compiling, and when i need full performance from games, i turn it back up to 100%. it's also good for limiting the heat if i put the thing on my lap. i run distributed processing programs like setiathome and distributed.net in batch scheduling, and i'm almost always compiling something, and with those tasks, throttling down to 75 is hardly noticeable.
i can't really offer any real recommendations because i only have an 8887, and don't know anything about the others. i ordered from pctorque, though, and it was easy, fast, and they answered my questions promptly. so i had a good experience. much better than dell, who took forever to get me my previous laptop.
but actually, if you think about it, games should _not_ be very cpu dependent, like they are with the ati drivers. maybe it was that way back in the day, but now it is more and more dependent on the video card. video cards have gpu's, which are actually real processors (at least, in nvidia's case - don't know about ati). the only time it would be largely dependent on the cpu was if you were using a software mode - software directx/opengl, software transform and lighting as compared to hardware T&L, etc. but as video cards are getting more and more advanced, more and more of the work is being done by the card, and the performance is not _as_ bottlenecked by the cpu. although not completely cpu independent, games really should not be 100% all the time as with the ati drivers. i'm hoping they fix that in the future.