Dish network and a tv tuner card?

Yes, you still have to use the Dish Network receiver; you have to run the output coax to your TV tuner, which in essence becomes a capture card, because you can't use it to switch satellite channels, only capture the feed like your TV would.

Yes! In that case not only can you change channels, but most of the media center programs will log on to your local cable network and download program guides, making it really easy to set up recording.

Same problem. You can pick up over-the-air (OTA) digital programs through an antenna, but if you want the same service as provided by the cable company, you have to run it through their channel changer box, first. Then you get an analog signal out, to your tuner card. The cards used inside PVR's like TIVO are licensed and not available to plebians like us. There is talk of releasing them to the public, but you would still, more than likely, have to "rent" them from the cable company.