well, in that case, i'd hold off on getting the 17-40. if you've got the 18-55, the 28-70 and the 50/1.8, you're well equipped to become familiar with the camera, see what you like to shoot and then decide what lenses make the most sense. 17-40's pop up for sale almost every day so they'll always be there for you to grab if you decide that's the range you use the most.