IMHO with a single GPU, and if you will primarily be using the system for gaming, get an i5 750 and OC it to ~4GHz. It's probably not worth spending extra for an i7 860 unless you'll be doing a significant amount of encoding.
How much do you want to spend ? also have you already got your motherboard ? if so,then is it X58 or P55 ?
Well if you are going with X58 go with i7 930 and if you are going with P55 get i5 750 or i7 860. The main difference between X58 and P55 is that X58 supports SLI/CF @ dual 16x mode(whereas P55 supports it @ dual 8x) and also socket 1366 CPUs usually OC better than 1156 ones and you can upgrade to 6 core CPUs later,aside from these 3 points there aren't any differences and also a P55 combo(CPU and motherboard) costs less than a X58 one.
Go with the x58 and An I7 920 d0 Stepping, spend the money you would save from buying the 930 on buying a heatsink...