The absolute creepiest thing I've experienced with this was put the goggles on and have the screens showing the view of a pair of cameras mounted on a telepresence robot in the same room. Then slowly pull the telepresence robot back so that I could see myself sitting there with the goggles on looking around in real time. It literally gave me the shivers.
But creepy out of body experience aside, the challenge then was control. Moving through space with a game controller with full view control can make you feel like you're a quadraplegic in the virtual world. Something that will really be awesome will be these goggles and a Leap Motion controller, so that you gesture around your world. You still don't get to walk (were are those 2D treadmills when you need them? [1]) but its more flexible than a thumbstick and a d-pad.
[1] http://spectrum.ieee.org/automaton/robotics/robotics-softwar...