I think you should go for the i7 rig. It would be cheaper to upgrade the gpu( maybe a 4570 x-fire, or a new 5750/4850), rather than with the i5 rig where it would be more expensive to upgrade the cpu (to the i7).
Keep in mind that this is a laptop and unless the videocard is removable, then there is no upgrading it.
If i had the choice, I would go for the i5 system. Sure, the i7 is a faster processor, but you will be getting more power out of your videocard in the i5 laptop and best of all, the i5 is not a bottleneck either. The odds are you will see better performance with the i5 laptop.