Well, most people here (in the US) are returning their new HD sets, because they tend to bring out the worst in analog pictures - especially low-bandwidth cable/DSS channels. The highest resolution source many people use is DVD, which is only SD.

Recently, I made a DVD from two video sources - a digital camcorder and an analog Hi-8 camcorder. On my regular TV, I noticed a distinction between the two sources, but it wasn't very apparent to my wife. When we later watched the DVD on our friend's new HD set, the video difference was night and day. The digital video looked great, and the analog video was atrocious.