Just like how cyling is about the engine, not the bike, photography is about the eye, not the camera. The camera is a tool--a bad one can hold you back but a good one won't make your pictures any better. I had a 10D and now have a 1D, the improvements in the 1D make the camera more durable and easier to use (especially quickly), but everything that is in the 1D that allows the photographer to take good pictures is present in the 10D.

Some of the minor touches that make the 1D nice most people would never even notice, such as an adjustable diopter in the eyepiece, an integrated eyepiece shutter (to block light from entering during long exposures), extreme weather sealing, dual memory slots (and the ability to shoot to both cards at the same time in the same or different formats), control layout designed for fast adjustment (less intuitive, but easier to change settings quickly with one hand), faster/smarter autofocus, higher frame rate, higher data bandwith/larger internal buffer, etc. None of these things would have helped Rad take a better picture of his bike, but for a pro, they can be extremely useful.

All you really need in a camera to take a nice picture is a good eye, a decent lens, and some degree of control over the exposure. Edit: and good lighting...