First, I have some really nice DX lenses that I would be putting out of service without a more modern crop sensor body. This photo shows the camera with the Nikon 12-24 zoom. This lens is a little wide for my taste but I am trying hard to make it my friend and it is an excellent lens.
Second, the D7100 is a 24MP body so it doubles the resolution of my current full frame Nikon D3s. It also features high speed crop like the D2X does and lets me crop in from the standard APS-C magnification of 1.5X to a full 2X at 12MP. My 70-200 F2.8 lens becomes a 140-400mm F 2.8 lens. That is awesome for sports like soccer.
Third, buying a D7100 instead of a D600 saved me $1000 and with that savings I had enough money to order a Fuji X100s.
Now everyone knows that 2 cameras are better than one and after shooting with Noah's Leica I am seriously looking forward to the Fui rangefinder camera.