I currently have the HDMI going straight to tv and HD still looks great. However non hd is neither better or worse. Basketball games, motorcross, anything with a lot of motion is degraded, either through the tv or the receiver. This is of course non hd. There is a chart in the back of my onkyo manual that shows inputs/outputs for all resolutions. If I use HDMI in the upscaler on the receiver does not affect it.

Suppose that a 480 dvd is better than 480 broadcast. If I had a poor cable signal as far as the 480 goes would this cause the outgoing upconversion to be worse even if showing to be in 1080i?

If I was to change the output on the receiver to 720p, I wander if I would get a better picture (one without overscanning (this is what I was told happens if you set the plasma to just scan))

Hope to gain a wealth of knowledge and maybe use it.