I use the D7100 along with the 80-400AFS VR, this is an excellent combination.
The D7100 has the full 51pt focus system, with the added benefit that the AF array covers a much larger portion of the image than on a full frame camera. The only limiting feature may be the small buffer, but there are things you can do to maximise this - use the fastest cards (I use the 95MB/s Sandisk Extreme Pro cards, they do make a difference), reduce file size (maybe even JPG if that suits), or there is a useful 1.3 crop option which increases frame rate and effective buffer.
The 80-400 is excellent, about the only limiting feature is that it's only f/5.6 on the long end. Other than that image quality is great, as good on the long end as the short end, good zoom range, easily handhold able.
Within the Nikon stable you'd have to pay a lot more money to get anything better.
Fiend wrote:How about this lens?
I acquired one for use with my D7000
Military Aircraft Every type from fighters to helicopters from air forces around the globe
Classic Airliners Props and jets from the good old days
Flight Decks Views from inside the cockpit
Aircraft Cabins Passenger cabin shots showing seat arrangements as well as cargo aircraft interior
Cargo Aircraft Pictures of great freighter aircraft
Government Aircraft Aircraft flying government officials
Helicopters Our large helicopter section. Both military and civil versions
Blimps / Airships Everything from the Goodyear blimp to the Zeppelin
Night Photos Beautiful shots taken while the sun is below the horizon
Accidents Accident, incident and crash related photos
Air to Air Photos taken by airborne photographers of airborne aircraft
Special Paint Schemes Aircraft painted in beautiful and original liveries
Airport Overviews Airport overviews from the air or ground
Tails and Winglets Tail and Winglet closeups with beautiful airline logos