most good hdtv's will upconvert 720 to 1080i, if im not mistake.

Only recent ones. Mine is a couple of years old. When it was made, it was one of the best available. But it was made before ABC went on the air with HD programming. It won't upconvert 720 to 1080. My HDTV decoder box will do the upconverting, but pixel conversion always involves trade-offs (usually bilinear filtering to hide aliasing due to the conversion).