any of the new sandy bridge processors...the processor will depend on what you plan on doing with the computer...for gaming, I would definitely say the i5-2500k..its priced at $230 and you get great bang for your buck..if your going to be doing anything that requires more resources/threading (photoshop/editing) then the i7 2600k. The two processors I mentioned are unlocked, meaning you could overclock it to get great performance. However, if your not into overclocking, get either the 15 2500 or 17 2600.