I won't go into the "it's not the gear it's the photographer" rant because you touched on it already (spoil-sport!
), but I will go onto another rant just the same:
These days, our cameras are computers. Moore's Law (or, perhaps the bastardization of it) says that computer performance will double every 2 years or so. This means that the camera designers have a lot more horsepower on that little DiG!C IV processor than they did with the brand-spankin-new DiG!C III processor that is in the 40D. This allows much better image processing in the lowly little Rebel than in the vaunted 40D. Not only that, but those great supercomputers the engineers are using are allowing not only better design of image sensors today, but helping to squeeze more out of the image processors themselves. It's no surprise that, technically speaking, the images are better exposed, better focused, and have better resolution today versus two years ago.
Now, that said, does your 40D take a bad picture?! I would guess not (from direct experience
).
Go. Enjoy your camera. Technology marches on; so should your photographic technique! 