Being old school and coming from cameras that had no light meter installed many, many years ago I believe a fast prime is mandatory for someone who desires to really be a photographer. Modern zooms are amazing (use em all the time ) but they produce good images requiring near zero thought on a modern Nikon. In good light conditions it is often point, wait for the beep and fire. Voila a more than instagram worthy shot. Couple that with some good software to crop and all one needs to do is get good focus and ok composition. Modern magic can do the rest.
Bokeh, lens speed, depth of field however often become accidental after thoughts when I shoot that way. Precisely why I often go out the door with only a prime lens attached, I want to keep my eyes and wits sharp - it took too much hard work to understand how to "see" what I want before I press the shutter......and everytime I go out the door with just a prime I see something differently and learn something new!
A fast prime attached to a modern Nikon is a wonderful thing! It makes you learn and think and try to use all the buttons the way the engineers at Nikon intended. The way you think about photography will be forever changed!
I recommend the AF Nikkor 50 1.4 D. after that consider some manual old school Nikkor Ai glass. No need to spend a bundle be patient and wait for the deal.
Good luck