For all intents and purposes, the Canon Digital Rebel / EOS 300D is a paired down Canon EOS 10D. The limitation this camera has (by choice through the software) the 10D doesn’t. That’s not to say that this is a bad camera. Far from it. But when Canon decided to be bold enough to go for the entry-level DSLR market, corners had to be cut to get the price down to something very attractive. Those corners are most notable in the plastic casing, however while the 300D offers a 10D LE on the features, the picture quality is just as good.
Our recommendation would be to stretch to the 10D if you can (again enjoying a price slash since the 20D hit the streets). If you are new to the DSLR market and a Canon user then the ability to use your lenses on this model will certainly the main draw. If, however, you are completely new to this level of camera and don’t have a stack of lenses already, then it really has to be the Nikon D70 for its overall performance and superior handling.