I never feel I'm "behind in technology", but I just sold my XTi on Amazon Marketplace for $525. [Will wait for a couple of weeks to see if the prices of the 40D come down, and for Apple to support the 40D's RAW - no shooting project for now.]
My last SLR was a 1G Elan that I used for many years. There are a few things I just don't like about the XTi.
- Shutter noise. I mostly shoot when traveling, and want to do it quietly in churches, etc. The shutter is very loud on the XTi compared to my Elan.
- No quick dial. For exposure compensation and when using M, the quick dial is very important. Again, I shoot fast and on the go.
I know the 40D will give me back those things, which I treasure. And then I'm very excited about the C1-C3 modes. This way, I can set one for 200 ISO, highlight priority, optimum aperture for outdoor sharpness; one for high ISO, maximum aperture for dark interiors; and one with AI Servo, evaluative metering for sudden things that I want to shoot.
Instead of pressing so many buttons to change ISO and then click click click to go from F11 to F1.4 or 2.8, I can just switch the mode over and start shooting immediately.
Well, I don't have my camera yet, but at least in theory, those will give me a lot of benefits over the XTi for my travel needs. Of course, the huge downside is the extra size and weight.