The "k" version of the i5-3570 is overclockable and the non-k is not. So either go with the k version and Z77 chipset or skip the OC and get the H77 chipset for the non-k CPU and save some cash. The MSI board you suggested is way overpriced. I was able to redistribute your budget to get appropriate needs for GPU. The 7950 will surpass the 660 in any game and can be overclocked for better specs.