What laptop would be a better buy for Starcraft?

Hello,
Both laptops i'm looking at are Dell Studio XPS16. They have same everything (graphics= ATI mobility Radeon 5730). The diffence is for the basically the same price I can get an i7 720qm with blu-ray and 4gb ram or the i5 540m with 6gb. I know the graphics card isn't the best, but which set-up would give me the most bang for my buck?
Thanks!!
Javier

I use my laptop for WoW and soon Starcraft 2 and Diablo 3. I usually play shooters on my consoles.