This probably sounds dumb, but first person games where you can look down and see your legs. One of the things I loved about the original L4D. Helps so much for jumping (since I can look down while running away from the hoard and see where my feet are in relation to the edge I'm about to jump from)and helps prevent the immersion breaking jolt I always get when I'm at the top of a stair case or cliff ledge and look straight down in and its like my character is a video camera with an shotgun duct taped to the side.