HTC Vive Prototype with Controllers (Source)
The HTC Vive is similar to the Oculus Rift, but adds two sensors which can be mounted diagonally in a room to allow you to physically walk around in the room, in the virtual reality space. Requires a powerful PC, similar specifications to what is required for the Rift. Also like the Rift, despite being able to stand up and move around in a simulated environment, the headset is tied to a computer by cables which need to be carefully handled to avoid creating a trip hazard.
Tilt Brush - An application that lets you paint in a 3D virtual world with amazing results. I've had the change to use this and was suitably amazed.