I wish to replace the rental DVR I get from Comcast, so I have investigated PC HD tuner cards (plus, I have many extra hard drives). I want to watch my cable on a TV and still be able to use my PC as a computer. Does such a device exist?
Unfortunately, going full screen in Windows Media Center all but disables the secondary screen. If you don't mind watching cable on your TV in Windowed Mode, it'd work fine. I don't know of any way around this.