I'm currently working on a virtual reality game where you are in control of a wizard and use your own hands to cast spells. You can throw fireballs (and other spells) at zombies by moving your hand through space. We're using the Leap Motion hardware device with a VR faceplate mount. I'm designing the game around the VR platform and the Leap Motion controller, but I am also supporting standard mouse, keyboard and monitor, and any combination of hardware configurations.
The leap motion hardware device does have some limitations which I don't know how to work around. The biggest one is character locomotion. Using just your hands in 3D space, how do you instruct your character to walk forward or turn, in a way which is fast, responsive and intuitive to players? I don't know. Nobody seems to know.
What I'm really looking forward to getting my hands on are the two hand held VR controllers coming out from Oculus and Valve. You still get hand positional tracking, but you also get button controllers which can be used to layer on input controls. The wii mote was just the beginning for what's coming down the pipeline ;)