Media center + tv tuner?

[fooz]

I'm looking for a wireless device like the media centers out there that allow you to stream music and video from your computers to your stereo/tv, BUT I would also like the device to transmit the other direction. In other words, I'd like to be able to watch TV/movies on the computer from the TV/cable.

Do these devices exist? From what I can tell, the media center devices are only intended for the former. And I'd really like a cheap slim device as opposed to building/config'ing/maintaining a computer for it.

-fooz