I would tend to agree with slayer. I don't see the 930 being significantly better than the 750 unless they somehow incorporate the ability to utilize hyper-threading into Crysis 2. I personally think that is unlikely, but don't quote me on that...
Other than that, in my experience, triple versus double channel memory is not that big of a difference for gaming. If this is more-or-less a purely gaming machine, I think the i5-750 will be more than sufficient enough, unless you just have money to burn.