so i got a 17-40mm for free from a relative, and while i have been spoiled by L quality lenses, with this one being no different, this is my only lens and i definitely am not in desperate need of the quality that this lens can deliver. what i do need is more focal range. that being said, what would be a good choice? the money that will be used will be whatever i get for the 17-40mm. i originally wanted a 17-85mm (i had a 28-135mm before), but it seems like im in the price park of the 15-85mm. or even the 18-135mm would be okay with me. i would like to try to get one of those lenses plus a telephoto lens, but if the 15-85mm is worth the price then i will consider it. thanks for any input!