Hello, I just purchased a Nikon D50, body only. I am looking for a good walk around lens. I can spend up to 500, but I am willing to pay a little extra if it is worth it. The two things that are important to me is that I want a fast and a sharp lens. I do not need one that zooms super far, but it will be my only lens, so it has to be versatile. I looked at dpreview, but it just confused me more. Anyone have any good suggestions?