Yes, you need the receivers. As least one for every two regular TVs and one seperate for HDTV.
I have not seen the new dish, so I don't know if it has 2 or 4 lines coming out of it, probably 4. DirecTv dvr's have 2 tuners so you do need a line for each tuner, plus one line to each of the other 4 tuners, 6 lines total. I would suggest you get a...
The Dish network HD receiver is all you will need to get HDTV. Some Dish network receivers even have built in over the air HD tuners so you might get local HD channels with a set of rabbit ears. Going this route you would/will never need a separate s...