Also, only 300 boxes for beta? That seems a little small.
EDIT: actually the latest answer in the FAQ is interesting:
"Am I going to be using a mouse and a keyboard in the living-room?"
"If you want. But Steam and SteamOS work well with gamepads, too. Stay tuned, though - we have some more to say very soon on the topic of input."
Something new on the input device front? Oculus Rift?
Valve sure is good at hyping things.