Be sure to check on lens compatability as well. The Rebel XT will be able to use any lens made for the EF and EF-S mount. I remember reading something about the D40 not being compatible with all of the current Nikon lenses. Something to do with the auto focus motor not being in the body, instead it has to be in the lens. Someone please correct me if I'm wrong. Be sure to ask the sales person about this.