I got my rift a few days ago and have been blown away by the games and the demos but one thing stands out Half-Life 2.
It's the first real story based game to be given support and I have never felt like I've been in a world more than playing this on the rift.
City 17 is huge and empty, every little detail is given life through the 3d, head-tracking and position you are in the world.
There is NOTHING like, standing there in the room with the characters talking to you feeling like you're there, or having your gun really held in front of you and you pick of the enemies.
Everyone has to try this, I have no doubt it is the future.