I have a line to get discounted intel procs, so if I keep my existing mobo I'm wondering what the best proc my mobo can handle would be. Looks like an i7 of some kind. Honestly I haven't had a chance to look extensively but I'm having trouble verifying compatibility.
That being said, in a larger bottleneck sense, I'm sure a faster proc would be beneficial, but in terms of gaming I have a GTX 470 super overclock edition:
here are a few to look for the Intel® Core™ i7-860, Intel Core i7-870, or the Intel Core i7-875K. They are the best that your board can support. However if you are gaming I would just try to overclock your Intel Core i5-760 over trying to find one of these processors.