A regular DirecTV receiver gets you standard def (~480i but varies by channel on DirecTV.) A DirecTV HD receiver will get you 720p or 1080i (depending on source) which you can scale to Enhanced Def on your TV (480p, aka "DVD Quality") which is about twice the resolution of SD. On a 42" screen you'd notice the difference.
Note - that this requires you to subscribe to DirecTV's HD package. Another option, if all you want are the network channels in HD, is to hook up an OTA (over the air) antenna to your TV since it has an built in HD tuner. In fact, you may want to try this anyway.
We just bought the Panasonic 42" plasma in EDTV (TH42PD25). It says it has an HDTV Cable Tuner and an HDMI Input.
My husband and I are having a debate - he says we should just get the regular Direct TV Receiver because since we don't have an HDTV - that's the best signal we're going to get anyway. I thought that if you had a built in HDTV cable tuner - you could convert down the HD signal to the highest possible pixel ratio your TV will support (which in any event is better than the regular Direct TV signal).
Does anyone have the final word on this? Which receiver do I need to get from Direct TV to get the best possible picture?