You dont really need the i7 if your just gaming, the difference between an i5 and an i7 in gaming is ~2 frames. You only need the I7 for video editing or a task which uses hyper threading (Most games dont support it just yet).
The i7 only really makes a difference if you are doing tasks which make use of hyper threading (which i believe only the i7 suports? correct me if im wrong) these include video editing an 3D modeling. For gaming the difference between an i7 and an i5 is 2 or 3 FPS. Not really worth it for another hundred bucks.
All in all: Save the money, go for the i5, spend the extra on a better graphics card (Like the 660 ti Power Edition)