Both Canon 20D and SD500 serves the different purposes. Canon 20D is DSLR and requires many SLR lenses for many shooting aspects, for instance, the extreme lighting condition and the noise control features, provided that you want to take photography seriously. Canon SD500 is a very good point & shoot, easy to carry around while shooting pictures for a very crip and clear quality. There's no absolute formula whether which one to choose and good for what. I'd say that the shooting ability and perspection of photographer is more relevant. Don't overinvest for what you will not use unless you take it seriously. Good luck.
I currently have a canon s410 camera. I want to know if I should get the new Canon SD500 for the hefty price of $500.00. Is that money really worth the extra 2.1 pixels? Should I buy the camera or just save to eventually purchase the new digital rebel 20D?
Thank You for you time