I got in, as well. Just sent off my signed documentation back to Valve. Looks like they're shipping on Friday. Super excited!
(Man, and this is right after I got Google Glass, a new TV, PS4/Xbone, and a Nexus 5. I have too many toys now!)
I'm also anxious to see if I'll be able to, at all, use my Oculus Rift with the Steam Machine. I guess I'll find more out later! Can't wait to try out that controller.
Congrats! I hate you!