Thanks for the suggestion iDroid.
Question 1. What makes the i5 processors ending in a K better. Like the i5-3570K?
Question 2. Can I split the two DVI ports to do four monitors? Or would I just buy another GTX 660? If I had to do another GPU would I need a larger PSU.
the suffix "K" means that the CPU can be overclocked.
the only reason i linked an Nvidia card was because i tought you might be doing some simulations and CUDA can come in handy for those situations... if not i would have recommended a 7850 which can output video to four monitors and has a MUCH BETTER performance in OpenCL applications.