You have both cable and Dish? And don't have locals from either? That seems odd. Or are you just refering to HD channels? You would have to pay more for those, although you could get them cheaper in the short run from cable since there would be no equipment to buy. Depending on what channels they offer, of course.

Anyway, if you can handle only Svideo from your DVD players, the cheapest route is to go ahead and run everything through the receiver and run your antenna straight to the TV for local HD channels, I believe it has an HD tuner. You'll have to run audio out from the TV to the receiver to get surround sound. So it will be a monitor except for locals, but that's only one digital audio wire running back to the receiver. (unless you pony up for HD from cable or Dish)