Yes, from all reports the III is the way to go. I've been going thru some of that FX "loss" myself recently shooting lower res FX for birding. Well for the first time, I am going to give high res FX a good go this weekend.
With the D800, we don't really have any "loss" to speak of, since the D800 equals or out-resolves all other Nikon DX cameras unless one happened to own a D3200, so it is going to be very interesting to try out
I am going birding this weekend so it will be fun to try. Hope we get some subjects (of pretty much any kind) in decent range. Distance is the killer with birding. This is Canadian Thanksgiving so I've got three days (and three mountaintops) to search for migrating raptors. Bit of an exploratory trip so we don't really know if we'll get any close in views or just distant ones.