oh no... Canon...
it isn't worth to sell your 20D for 400D. This is Fat Chung's Advise.y u need a 400D? lighter? or the dust off feature? increase in megapixels doesn't mean increase the picture quality. and also, the 10 megapxiel is alrdy over the lens resolution limit. unless, u want the 400D because of its weight. Even, if u want a light, there r other options.