Others who may know more than I can chime in here...
EDTV is a TV with less resolution than a true HDTV and they down convert the
HD signal to work on the lower resolution.
If you want a HD set... You should consider...
1. There are many out there that support many different resolutions...
They are measured by the number of horizontal lines. Current NTSC (regular TV's) are 480i. Then we can talk about interlaced or progressive.
720p 1080i and 1080p.
The holy grail right now is 1080p...
Yet a good DVD only supports 480p at this time. The new Blue-ray or HD-DVD's
will only support the 720p as it's highest (currently).
Some broadcasters are transmitting at 1080i....
So in short. Get a true HDTV that supports 1080i...
I hope this helps..