I have a 42" panasonic EDTV (model no. ?) w/ built-in ATSC tuner and rabbit ears w/UHF loop. And even on that you can see a big difference between HD and SD.
I don't receive any channels in dolby 5.1, only 2.0 surround. Is this what everybody else gets? One day close to New Years, I was able to tune Houston's ABC affiliate and that was the only time my receiver lit up as receiving 5.1. Haven't been able to get that channel again since.