I am admittidly ignorant on this matter. What is the difference in DX and FX in Nikon cameras? Is one better.
Your D80 is DX, film or the D3/700 is FX. DX is a step backwards IMO, and FX restores what lenses were designed to do. I'd be careful about shooting ISO 1600 on a D80/200, ISO 1600 on a D3/700 looks like ISO 400 on the D80/200, nikons FX bodies can shoot up to ISO 25600.