I don't really agree with the notion that 'desktops are over 5x faster than notebooks' and that's that.
The GPUs are much faster, sure, but between things like processors and 'effective' RAM it is fairly close.
I'd recommend an HP dv6 or dv7 with the AMD 7690M (Renamed 6770M, identical to desktop 6670)
It has 480 SPs, 725 MHz core and 800 MHz 1 GB GDDR5
It has a 1080p upgrade option, and the quad editions have an i7-2670QM, which is a slower, less power hungry version of the revered desktop 2600k (It has hypertheading while the desktop i5-2500k does not.
I can play all those games at high settings on mine just fine.
It might not be as fast as a desktop, but if you don't already have peripherals, a monitor, or desk and want decent gaming power you can carry with you, I'd recommend it to anyone and it has served me well for nearly a year. (dv7t-6000 quad edition)
However, there could be hardware updates around the corner in a couple months.. that one's your call
EDIT: I just noticed the guy above me recommended the same thing.