20D is a 8.2MP camera
Rebel XT (350D) is a 8.0MP camera
Rebel (300D) is a 6.3MP camera
There are many differences between the 350D and the 300D, the 350D is definitely worth the extra money over the 300D. The 20D is a high end prosumer digital SLR but the differences between it and the 350D are few. Still, I pine for the 20D...or better yet the 1D MkII.
If you're looking to get into a digital SLR though I'd recommend the 350D. The big money will, and should, be spent upgrading lenses anyway.
