you could always connect the hd cable box on a different input for the tv... configure each input for its source via dvd or programming...

on a side, i have hitachi 65swx20b, which is the predecssor to the s500. i have run the setup discs on it, but it was way too dark when "properly calibrated". in general i found the setup discs to do very little as far as improving the video quality... at best they are a reference point to move away from until you get the picture to where you like it.