I've been playing games with the Oculus Rift for about a month now, and I can honestly say the experience has been astonishing.
Still in development by OculusVR, the virtual reality gaming headset I've been playing with is essentially a prototype, with planned improvements to the consumer version to include HD display and wireless capabilities. Despite this 'development kit' being non-HD, the depth of immersion this piece of hardware creates for the user is nothing short of mind-blowing.