Earlier quoted context omitted.
I use my Xbox 360 controllers with a no-name wireless receiver. It took some work to get the drivers working properly, but it's fantastic now. If Valve can provide a similar experience, except all plug-and-play, that'll be killer. I totally agree that it's non-obvious to most of the gaming market, though.
Can you share where you got your no-name wireless receiver?
http://www.amazon.com/Xbox-360-Wireless-Gaming-Receiver-Wind...