I bought a 20D last Fall with the 18-55 kit lens and a used 75-300 EF lens($70). I can recommend the 20D for the way it's built, speed of response, 9-point or spot focusing, the ASA3200( I use that feature often for low light candids, etc. I invested in Photoshop CS2( and Noise Ninja plug-in) which allows photomerging to get 30-60meg raw files, producing results equal to a 20+ meg camera. The HDR( high dynamic range) feature allows merging several differently exposed images to produce 32 bit images with 12-14 F stop dynamic range. In other words I put my money in the body and the software to get capability beyond my expectations.
In fact, you might explore these enhancing software features with your 10D before selling it. With PSCS2 Photomerge you should be able to get pinpoint sharp 24-30" prints.
Both of these features are covered on this web site.