In the released videos so far, we see a man combining the Omni with an Occulus Rift headset and running around gunning down enemies in Team Fortress 2. Another is seen strolling through Skyrim.
Certain in-game features would still require a controller, but throw in some Kinect support (which is already there) and we're starting to see some pretty impressive Virtual Reality gaming in the next year or so.
The source link contains a video and it is cool as hell. Klick and watch it :-D.