I am currently shooting with a Nikon D80 and the lens that came with it, the 18-135mm. I'm really bored with that lens and am looking to get a new one. I have the price range between $300-$400, so does anyone have any suggestions? I want either a Sigma or a Nikkor. Also, I am fairly positive I am also getting the 50mm/1.8D as well. Good lens? Thanks for any help!!!