Yeah the 8700m stuff is terribly spendy. 7700 and x1700 are pretty much the same, just as the 7600 and x1600 are. Personally I'd go for the Asus with the 15.4" screen and the Radeon card. You shouldn't have any problems running new games well.
My notebook:
2.0ghz Turnion 64
2gb pc2700 ram
256mb Radeon x1600
I've had no problems at all running new games at medium or even higher settings. Oblivion and FEAR ran at at least Medium settings without a hitch and Act of War was maxed if I recall correctly. And those Asus laptops are faster in every way (especially the processor) so you shouldn't have any problems with either of them.