I'm looking to buy a new lens for my D80. I have the 18-135mm & the 1.8/50mm fixed lens, but I really find that the 18-135 is quite low quality. Which it is of course because its a kit lens. I'm interested primarily on portraiture, but a wideangle isn't necessarily out of the question either. Really i'm looking for a good quality lens <$800. Any suggestions to what good quality lenses I can get for under that price?