I purchased the 20D as an upgrade from my Digital Rebel. The cost was certainly worth it.

This camera has many, many advantages to the Rebel (as I'm sure other reviewers will point out), but I thought three were worthy of mention:

ISO 1600 and 3200 have very, very low noise. This means that I am now able to get low-light shots that I never could before. For example, I often take pictures of crowded streets at night. Before, I needed to use a flash or else my shots would be blurred by camera shake and the motion of people walking. Now (with the help of a f1.8 lens) I can set the camera at ISO3200...