"Why did you choose the D600 over the D800 or D800E?"
That's an excellent list Mark. For me it essentially came down to evaluating the mix of price : weight : my needs.
I know that the D800/e is too much camera and too much cost for my needs and even if it wasn't, the size and weight of it would see it stay home too often for me to have justified the purchase. True the D600 is no lightweight but for FX it is as compact as it gets right now.