The Vivitar Series 1 90mm f/2.5, was made by Tokina, and is a very good lens. One of the sharpest lenses ever made. By anyone! The Kiron 105mm f/2.8 macro, is a phenomenal lens. It goes 1:1 without any adapters of any type, and is sharper and better built than the Nikon equivalent. With a touch of diffusion, it's also a superb portrait lens.
Mike, what focal length of lens are you looking for?