Nikon 85 F1.8 AF D lense

I shoot primarily with the 85mm F1.4 AFD. It's a fine lens and I never saw any reason to move to a G. To be honest, if I ever changed to anything else, it would either be to the older ais, or to the Zeiss 85mm F1.4. I'm also nuts and shoot manual only most of the time, so having a big focus ring is important to me, and the D and G focus rings are flimsy and were built for folks who rely heavily on autofocus. Still, the D has performed well, I have taken it to some pretty harsh environments too. It held up quite well in Cambodia and did well in India. If anything a move to FX would be the next step. I started shooting with my 85mm F1.4 AFD on a D300 as well, and after moving to the D700 I noticed a huge difference in results and performance. Autofocus, when I do use it, is faster and more accurate I find. Although that's going to be case by case, some people will have a different experience than me.

D300 examples

http://www.flickr.com/photos/jonsiegel/4686554978/

http://www.flickr.com/photos/jonsiegel/4707366937/

D700 examples

http://www.flickr.com/photos/jonsiegel/7320183614/

http://www.flickr.com/photos/jonsiegel/6270290430/

I would put any extra money you got towards FX, unless you're into birding or shooting nature, in which case the extra reach DX gives you is worth it to stick with it.