Have a 350d (rebel xt) and a 17-85 IS lens. I want to sell the 17-85 because it is too slow for me. I was thinking of just getting a sigma 30mm f1.4 for now since i'm on a crop body and possibly a 70-200 later down the road. I had a 50mm f1.8 but it was too much for a walkaround. Anyways, my limit is about $600.00 (college student w/ no job ftl). What do you guys suggest I get? And please, no L glass that's out of my price range and I don't care that 3rd party manufacturers aren't as great as canon.