I picked up an old Ai series 135mm f/2.8 lens today at my local camera shop. It's a 1979 or 1980 version, in absolutely mint condition. This was one of the most popular short telephotos of its day and a superb lens for portraits on 35mm. My two choices for portraits when shooting with the F3 were always 85mm and 135mm. The 85mm on DX sensor returns 130mm so is a good halfway house. I had one of these 135's years ago and it got stolen. Nice to have one back in the bag now and on the DX sensor in my D300 it gives me a 200mm f/2.8 in an absolutely tiny package. Bokeh is superb at f/2.8 and evern great at f/4.
Nikkor 135mm f/2.8 Ai - manual focus - @ f/2.8