I've always heard that the 24-85 AF-S is a very sharp lens, but never used it myself. Moose Peterson, a wildlife shooter, actually went to that lens instead of the 28-70 f2.8. That lens is one of Nikon's best and about four times the price - to give you an idea of his opinion on the 24-85.

I've had the 28-105 f3.5-4.5 for a few years and been very happy with it. It's excellent in it's price range, probably the only down side with the lens is that it's almost impossible to manually focus it (if that's even a concern).