Currently I have a D40X with a 50mm F/1.8. I have 3 basic choices: 1. 18-55 kit lens (only for the wide angle zoom) 2. 55-200/70-300 lens - Telephoto is nice. This would be a basic lens, F/3-5.6 or whatever the cheapest ones are. Possibly a Sigma 70-300 APO-DG 3. Some sort of a macro lens (used, for a good price). Any suggestions? Would an extension tube work as well? I am leaning towards the 18-55 and an extension tube, because those are cheapest. I would like to keep it under $200. Does anyone have any good sites for used lenses? I can't seem to find any with a quick search. I am located in Canada but I can buy from the US.