Consider the 24-70 HSM sigma or the Tamron 28-75 as well. I have heard good things about the 24-85. Its a great little walk around lens for FX cameras. I have not played with one but the reviews are ok for it. I was considering getting it myself but I already have a 35-70 f2.8 which is a great old lens. I am waiting for tamron to come out with a VC version of the tamron 28-75 F2.8. an updated 17-70 from sigma should be interesting too.. The best in this range is probably the 16-85 dx nikkor but I am kind of spoilt by my 35-70 F2.8.. so I am rather picky in this range now. sigh ... Oh and I have the 18-200VR so i am in a different situation from you.
The reasons I was considering the 24-85 is the F2.8 at 24 make it almost as good as the other mid range F2.8 zooms esp as a walkabout lens. Its range is nice esp for portrait on DX. Its small and light(compared to the F2.8 zooms). IQ and distortion is quite good. Its a Nikon.
Cons for me : I already have the 35-70. IQ is not better than the 35-70. Its aperture varies from 2.8 to 4. If I were to get it It would be for a specific purpose which is for stage shows weher the F4 at 85 is not a good thing .. might as well use my 18-200 VR. which is also about F4 at 85mm and will have VR.
What am I looking for in this range? F2.8, VR, bit longer than 70, bit wider than 35. = no such lens yet. well not for Nikon anyway.