My son in law wanted me to shoot a tree across the Kenai River in Alaska and down a half a mile of so because there was a bald eagle in it. I said that the eagle would be so small that no one could see it even with my 300mm lens. He said, who cares, that will show people what we have seen. Perhaps that is the reason some people shoot. I know that it is probably true for the gazlillions of pictures of people posing stiffly in front of famous places. The notorious, "I was there pictures!"
In fact, my national guide in China couldn't understand why I might want to shoot street scenes in China or shoot a picture of a famous site without someone that I knew posing in the picture.
Along those lines, there are a lot of people who don't care a whit about good pictures. They just want to see someone that they know in the image. My wife's sister was not interested at all in any of my pictures of China unless it had her sister (my wife in it). She told me, you certainly didn't shoot many pictures with Judy in them. I answered, that is correct, I didn't!
I can say that my experience using my 400D/XTI and now my 7D is that my picture quality is getting better or is it that I'm working harder with this new equipment. I still have problems with composure and "seeing" the shot. But I keep at it and read, study and view other photos that I admire. So, it's a good question as which is more important, the photographer or equipment. For me, I'm working at using the equipment to their best standards and as a photographer, learning and working to get the shot in the camera. As for equipment, I think the lens is more important that the camera body, but that may open a whole new area for review.
I aagree with the lens being the most important facet. I once used a 30D and a 40D with the 17-55mm f/2.8 and 70-200mm f/4L IS lenses. My imagery was quite good with the older 30D. I switched to a 40D and 7D combination with the same two lenses for the better AF of the 7D, not because I didn't like the quality of my 30D imagery.
I wouldn't mind a second 7D, just because I love the focus capability of that camera and I'd like to standardize my gear. That way switching from camera to camera in the field might be easier and both the cameras would use the same battery.
OTOH, the quality of my 40D imagery is quite good and I don't really want to invest the extra cash in another body...