I have a similar spec laptop, a Centrino Duo T7200 at 2GHz with a 7950GTX and 2MB of RAM. I like to use the 1280x800 resolution, it plays well with full detail but if I go and add v-sync and anti-aliasing (x2) I drop down to 30FPS. I'm constantly adjusting the settings and not really happy.
This is a great website and you can see which the REALLY fast laptops are. Mine's currently 10th in the top 10 the Voyager 720DC Plus.
http://www.reportlabs.com/testbed/ve...nbtop10gra.php
Perhaps it will help you decide.