With Canon bringing out a 50 Million pixel camera, Nikon will respond witha a simular if not better model. The Nikon D4 appeared in January 2012 so so will becoming up to the 4 year possible Model change .I made the decision to sell my D4 now, before any new models came out to help stop the depreciation which would decrease its value. I had a D4 and a D810 and found I wa using the D810 most of the time and the D4 was just left in the studio. This was due to my workflow changing but found the D810 coped well except for the very fast FPS rate if I needed that requirement.
Camera Bodies drop dramatically in price even more so, when a new model appears.
Thats life, but it still hurts.
Camera, Lens and Tripod and a few other Bits