17-35mm 2.8 or 17-55mm 2.8 on D7000? - I'll be using the lens for club shots, interiors, and events. I've rented both and am partial to the 17-35 for the way it feels, fast focus, and the Images seem to be sharper. I know it's an fx vs dx but I maybe upgrading in future and the rental lady was trying to explain that the crop factor doesn't apply to it. I havent compared pics but I didnt really notice a big difference. They both sure are $$$ but I'm just starting to make some cash with the camera and want to invest the lens rental fee and purchase. Any feedback?