[TurboFan]

XTi, 40d, 5d, - it's all equipment masturbation. Why does it matter what body a photographer has? Aren't you paying for their work? If the guy wants to use a pin camera or a Kodak Brownie, who cares?

Bottom line, the camera is a light tight box with a hole. Why do you want to trade in the XTi? What are it's shortcomings for you? I'm not saying you shouldn't do it, but I'm wondering what you expect the new camera to do that the old one can't. The photographer is the artist, the one making the image, the camera body is but one tool of the artist.

That said, I did choose to upgrade my DSLR about a year ago, but I was looking for a faster buffer, better AF and a higher frame rate. I see frame rate mentioned above - why do you need a faster one? I needed it because I shoot wildlife in Africa, and I bracket. I can shoot 7-9 frames of one animal looking for that expression and exposure combination. I'll probably upgrade again in 1-2 years as my current camera doesn't have a full frame sensor, but I'm still getting great shots w/ a crop sensor, so I'm not in a huge hurry.

To the OP, what do you like to shoot? That is another important question in determining an upgrade. The XTi is a great beginner camera, and I can see wanting to upgrade, but remember, the camera isn't making the image, you are, so don't expect your photography to improve with a new body. In fact, it will probably worsen briefly while you adjust to your new tools.