HP dv6t > customize > select HD5650 switchable graphics
HP DV6T Series
comes out to $799
of course there are the pros and cons (low resolution, upper midrange graphics) of going such a route.
its no monster gaming laptop, but gets the job done @ around $800
and plus, HP makes great laptops.
if you want a crazy gaming laptop though, you might want to try and increase your budget. there are some good laptops out there with Mobility 5850 or higher in them and nice resolutions of at least 1600x900 @ 15.6in. but they all come at a cost ._.
you can help us narrow your choices down, are you looking for a specific screen size or any other key things you want?