Last week, I was hanging out with a friend who had a 20D with quite a menagerie of lenses, ranging from the 10-22mm super wide zoom through the 300mm f/2.8 with all the bells and whistles. Compared to my Nikon D70, the 20D felt comparable -- not like the cramped grip of the 350D. The autofocus and such was also comparable, although everything was just slightly different enough to cause me fits.

The super-wide zoom was revelatory to me. I need to go out and buy the equivalent (and expensive) Nikon lens as soon as feasible. The extreme telephoto with image stabilization and whatnot is a fantastic toy, but you have to want to take the sorts of pictures that it enables (wildlife, sports, paparazzi things, etc.).