Analog TV--what we've been watching for more than 60 years--has a resolution that's equivalent to about 640x480 pixels. An HDTV program, on the other hand, has a resolution that tops out at 1,920x1,080 pixels, more than six times as sharp in best-case scenarios. The difference is obvious. One look at, say, a razor-sharp image of a crocodile rolling in the mud on Discovery HD, and you'll understand.