I'm just copying and pasting my response to your PM in here, so it will look like a weird response to some.
Not so recently, I've had the 20d for a year now
If I were buying a "semi-pro" dslr today, I would get the Nikon D200 (provided I didn't have any lenses for another brand of camera), but....I would hold out to see what canon comes out with at PMA, the 20D has been discontinued (and is scheduled to be replaced this spring, with the announcements of it's replacement at PMA later this month) so you can find it cheap, people are already selling used bodies in anticipation of the new model, so you can pick up a nice used unit fairly cheap, or you can wait and see what they come out with in answer to the D200. And then choose from there.
, the rebel XT is not a semi-pro dslr, it's an entry levels dsrl. It's a nice camera but the build quality alone makes the 20d worth the difference, not to mention the other differences. You got to ask yourself if you would actually take advantages of the difference, provided you feel OK carrying around a plastic camera.