You should get the 4690k over the 4670k. Although to be realistic, you don't need a $750 to build an mmorpg build. Take a look at this build:
PCPartPicker part list / Price breakdown by merchant
Basically, a cheaper CPU/mobo combo that will still be great, a video card with 3GB of RAM (if you want), a cheaper but still good PSU, and an SSD to improve loading times. The SSD will give you a much more noticeable performance increase than the CPU will.