If I've read the previews correctly, the main differences between the 350D and the 20D are: plastic body instead of metal, different proprietary battery, no ISO 3200, no circular wheel thingy on the back, small LCD panel above display instead of top-mounted one, absence of several Custom Functions which may not be useful to most people, 7-point AF instead of 9-point, and about £300.
Having the on/off switch alongside the mode dial is not the cleverest thing Canon has ever done, but in general it looks good enough to sway people away from the D70, and perhaps the 20D.
