Valve's Steam Machine beta includes newly announced Steam Controller
The 300 individuals selected to test the Steam Machine will receive a controller as well, but it won't include the clickable touchscreen and they won't be wireless. Instead of the touchscreen, which will be included in the final version, the beta controllers will have four buttons in its place. And the controller will require a USB cable to connect.
A small sacrifice to test what is arguably one of the greater innovations of this generation. You can see the requirements for participating in the Steam Machine beta here.