I am going to be getting a Nikon D7000 soon. I think I'm correct in assuming that the Nikon D7000 will use its own focus motor for an AF lens, but allow the lens to use its motor for an AF-S lens. I'm looking at 50mm prime lenses that are AF and AF-S. From what I understand, AF-S lenses are a bit faster, and possibly more accurate (are they?) but is it worth the extra bump in money (~$85) to go with the the AF-S vs. the AF? How does this question change at other lengths (35mm, 80mm etc.)? Is the answer the same across the board? (If the AF-S simply performs better, I think it's worth the money.)
Does it make sense to go with AF-S lenses now just in case I move to a Nikon DSLR that doesn't have an internal motor?