Hi. Rest assured I'm not spooked by the idea of a high resolution camera, although it's a race between higher resolution and my cataracts. I'm looking forward to the benefits of the 16-85 lens and D7100 vs. the D200 and 18-200. I also have the 80-400 which should more exciting with cropping possibilities.
However, I must confess the purchase was not only motivated by the search for better IQ and high iso benefits but a desire to reduce weight, both mine and the camera gear.
If I were younger I suspect I would have gratified my medium/large format envy and gone for the D800 but camera weight and big glass won't work now. Obviously, everything in life is a compromise but, at least on paper, the D7100 looks like a good bet.