I'll be going to B&H in New York this Sunday to buy some things for my Canon 20D. I'm planning on getting the Canon BG-E2, Canon EF 70-200mm F/4L(Most likely I'll sell it in the future for the 2.8 when I get the money) and a flash along with a bag, etc. Anyway, I can't decide on a flash. My choices are the Canon 420EX and the 580EX. I have the money for either one but if I wouldn't need it, I can use that money towards another lens, or the 2.8. Would the extra features benifit me much of the 580EX? Anyone own any of these? Opinions? I'll be doing a lot of sports shooting but I need a flash because I travel a decent amount and the built-in just doesn't cover it.