i'm a newbie, i own a nikon d40 w/ 18-55 kit lens, i'm thinking of purchasing a new lens, right now i'm trying to decide between a AF 28mm f2.8D & AF-S DX Zoom-Nikkor 18-135mm f3.5-5.6G. i love shooting street/outdoors but i also want something that i can use on family occasions/events. my...