The Canon EOS 50D is Canon's entry-level professional camera (for now - new ones come out about every 18 months or so, so the 50D is due to be replaced soon). It very capably bridges the gap between the Rebel series and the full-frame high-end professional series.

A colleague who already had a 50D told me that I would quickly come to love the thumb wheel control dial on the back of the camera, and he was right. Having two controls that allow me to change settings directly, without having to press any buttons, is very nice. By comparison, the Rebel XT has only the control dial near the shutter...