When I bought my D800 I knew that it was time for some new glass. All but one of my full frame lenses was bought when I was still shooting film on my F100.
I have the 85mm f/1.8 G. I was considering the 85mm f/1.4G but after doing a number of test shots back to back I decided that the f/1.8G would meet my needs, and leave me part way in my savings for either a wide prime (24mm 1.4) or a sharper wide tele. The owner of my local Nikon deal had both and was happy to let me test them.
I find the 85mm f/1.8 is sharp, and the contrast is very nice. With the D800 the narrow depth of field is quite apparent.