Never thought I'd be in the "travel lens" market, but I am. My 40D doesn't see as much use as it used to now that I've sold my 70-200mm and my 100mm macro, gotten out of sports photography, and picked up the G12. So I guess I'm just looking for a wide-range lens that "does it all" pretty well. I'm thinking of selling my 17-50mm and buying either a 15-85mm, 17-85mm, 18-135mm, or 18-200mm. Any recommendations on these lenses? I use flash in low-light conditions so wide aperture is not essential.