What are the differences between them? Besides the obvious of them being different models and being the Digital Rebel - XT - XTi. What are the pros & cons of each? I might possibly be getting a 300D soon (trying to save up what little money I have while forking out what I have to for bills instead of splurging and buying the XTi) but I'm just curious about the differences (big & small) to each one. Anybody know??