I'm wanting to upgrade my equipment, but I'm not sure the best way to go about this. I'm currently shooting with an XSi, and I have two lenses: the kit lens ef-s 18-55 and the ef 50. I mainly shoot with the 50 because it's highly preferable over the kit lens, but sometimes I need more flexibility. The body and kit lens were a graduation present that I didn't pick out, but I really enjoy this camera. Am I right to think that a new lens would help me achieve higher-quality images on my current body, or should I upgrade the body (and probably then only be able to afford another kit lens)? Any input is greatly appreciated; I'm a little overwhelmed by all the research by I've been doing. Thanks!