Thank you, I thought you might start this....
I am going to do this by budget and, I think adding the 70-200 f/2.8 and the 80-400mm f/4.5-5.6 is appropriate in the budget category for super tele.
D5100, 80-400mm f/4.5-5.6 Nikkor (used)
D7000, 70-200mm f/2.8, TC 20-EIII
D800, 300mm f/2.8, TC-14EII, TC-20EIII
D4, 400mm f/2.8, TC-14EII, TC-20EIII
D4 500mm f/4.0, TC-14EII, TC-20EIII
or unlimited and wanting to shoot extreme long shots
D4 800mm f/5.6, TC-14EII
The subject for me with the budget at $20,000 is in the race car/motorcycle objects, moving, along with sports, working sometimes with low light. Nature, birds, animals, also an interest. So, what I actually have is the D4 with 400mm f/2.8 and the TC-20EIII, TC-14EII and all of it performs in a manner beyond my wildest expectations.
I would note, however, for the most part, unless one is looking at images side by side, the $2500 category will produce the same images at 10% of the cost. And for those shooting D40's, a used 80-400 will also do what the $20,000 budget will do, but the "keeper" rate will be only about 20% of that which comes out of the D4.