If I were interested in upgrading to a newer DX body right now I'd either wait for the rumored update to the D7000 in a few months or look for a good deal on a lightly used D7000 body. The main advantage to the D600 right now, aside from FX, is of course the current technology IMO. Too, as far as FX is concerned you have two usable and good lenses. The 70-300 VR is FX. The 16-85 probably could be sold for just about what you'd pay for the FX version and that comes with the D600 kit, the 24-85. The choice is yours! Best of luck.