I am pretty much fed up with the d70s's AF performance and I am also ready to move up to a better camera. I am to the point where my d70s is holding me back. I am pretty sure that I'd like to buy a used d2hs. What kind of a shutter count should I look out for on a used camera like that? Also I know the image quality is great on a d2hs but up to what point? I have made a couple 20x30's on my d70s but i think the largest I'll go on the d2hs is 16x20 just because I see no need in printing big anymore. How is the quality at 16x20?

Quality at 16x20 should be very good. I've printed 13x19" with no issues. The D2 series shutter is rated to about 150,000 clicks... I'd still suggest going for one with 20-35k if possible.