I5-750. I will never recommend the i5-661 until the price drops significantly. You have a discrete GPU, so you don't need the integrated GPU. The 750 is a true quad core as opposed to the 661 dual core with hyper-threading (which is really a gimmick as far as gaming goes). The 750 will have far superior performance for the same price. No reason to ever get the 661 IMHO- way overpriced and quad core is the way to go these days.