This camera is my husband's and mine, and it is a beauty. It is an upgrade from the 40D, is a 15.1 megapixel, and has the new Digitech 4 CMOS processor. The camera has face detection in Live View mode, and has an improved ultrasonic sensor cleaner for the camera processor (cleans the dust off of the processor every time you turn the camera on). It also has the new CA mode (creative mode), and the LCD monitor has 920, 000 dots of resolution, which is an improvement over the 40D.
It has a solid magnesium body, does have a little bit of weight to it when you hold it. This camera is classified as semi-professional to professional. It is not waterproof and has a hefty price tag.
The camera is sold either as body only or in a camera kit which includes a lens, which is what we got. Body only is about $1400.00.
If you are in the market for a professional camera, the Canon 40D would definitely fit the bill.