Hi. I hope your ready for a very long read.
I think I understand what you are looking for: You want a high Circle of Confusion in your photos, which is mostly caught by the aperture range of f1.4 to f2 plus a very large Depth of Field.
In my experiacnes the best lens to capture those effects are as follows, in order of cost:
the Nikkor 50mm f1.4
Nikkor 50mm f1.8
Nikkor 85mm f1.8
Nikkor 60mm f2.8G (only on full frame sensors, the true range of the 60mm N is 2.8–4.3)
Nikkor 200mm f4 (Very old lens, but I still swear by it, kinda, mostly, okay so not really swear as much as enjoy)
Nikkor 24–70mm f2.8G
Nikkor 24mm SF f2.8G
Nikkor 200mm f2
Nikkor 500mm f4
Nikkor 600mm f4
Nikkor 400mm f2.8 (sweat jebus and all that is holly to you and I, this IS the only lens I would use if I always had the option to get far enough away)
Some other options to consider would be doing as some have suggested and giving a very large distance between subject and background, then shooting with a longer lens, providing a very good range of field. When ever I am out and about playing, I take my Nikkor 80–400mm f4.5–5.6 and shoot at the 400mm mark, even though I have an aperture of 5.6, I still get an amazing depth of field. In fact, some of my favorite photos to take are ones in which I use my 200mm f2, giving me an INSAIN DoF. Most people think I shot the photo with a macro.
The biggest thing to remember about Nikon is the fact that they are trying to “separate” themselves from “the old days” meaning most of their newer lenses are getting smaller, with fewer groups and sets, but with a greater quality of glass. Which means their lens are getting a lot lighter, and a lot smaller (unless it’s the 24–70, dang thing is to dang big for a dang portrait lens. but I still swear by that one, and I mean swear.) It also means nearly every new lens in the last 5 years has had ED or better glass (or that weird pseudo-ED glass) so most of the old “problems” like the CoC and lens aberrations are a thing of the past. Another consideration is the way the sensor gathers information, compared to a piece of paper burning up, and the type of camera and, the list goes on and on.
If nothing else, I have a plethera of saved masks for Photoshop that might help you judge your own DoF masks for creating false DoF’s and CoC’s.
Another consideration is Element Vignetting which a lot of old lens and some speciality lens have. I know when I use my 18–200mm lens on my IR D200 I end up getting a massive Element Vignette at 18mm and 200mm. THe 80–400mm does it a lot at 80mm too, unless I shot at a low aperture (as in a high f number, like f22)
I hope that helps. If you would like you can PM me or send me a lurve, or what ever the dumb name Fluther uses for a “Privet Message” to me and we can talk more in depth.
Oh another consideration is also precise focusing, if you ever upgrade to a D300 or higher (in my option you shouldn’t go any higher unless you are A) Rich or B) a pro) you can trick the camera into many strange things using the firmware.
So I hope that all helps, or gets you thinking.