The main point is that it begins and ends with the source.
You can only do so much with the 480i source on standard DVDs. You can well mastered discs look as good as the HD-Lite stations from satellite/cable, but they will not look as good as over the air HD broadcast locally.
The HD-DVD/Blueray CAN look as good as anything you can possibly view. Of course, some are mastered better than others.