Hi All, I have a Nikon D3000 with the 18-55mm kit lens. I am thinking about getting two more lens, one for macro and the other for portraits, landscapes, telephoto, etc. I was thinking about a 105 macro and a 18-200 for the other. Any other ideas? What brand of lens would you recommend? What do you think about Sigma and Tamron? I know Nikon is a little high in price. Thanks in advance.