> Then I started hearing of the dust problem and have read reviews
We all do, but I would take all those reviews with a grain of salt on the dust issue. IMO, the D7000 is not going to keep up with a D600 in image quality and high ISO situations, though it may never make a difference in your type of photography.
Sticking FX lenses on DX - no issue except for the crop factor. As an aside, I really like having my 24mm lens give me the same perspective I have with film since I still shoot both mediums.
"Extraordinary claims require extraordinary proof " - Carl Sagan