Contact other researchers who work in facilities similar to yours. I'm sure you collaborate with other labs that use HPC resources. Talk to them and get some information about how they do things there.

Personnel is really the key ingredient of HPC. Find someone, hire them quickly and give them the decision of what to buy.

The games the subjects were playing were either "Medal of Honor: Frontline," (violent) or "Need for Speed: Underground" (non-violent). Could it be that Medal of Honor (being a first person game) was more immersive than Need for Speed? Although Need for Speed can be an exciting game, it doesn't attempt to engage your emotions like a story driven FPS does.