Hi! My name is Mike and I'm a portrait lens addict. (Room: Hi Mike!)
Here are some of the lenses I own and have used with 35mm film in Nikon Mount for posed portraiture. You'll note that the 105mm f/2.5 is not on this list -- I decided to cover that focal length with a macro lens instead:
Tokina 60-120mm f/2.8 AT-X. I actually bought this to use as a portrait zoom on a DX camera, but it works quite well on film as well for couples. At least in the U.S., this is a bit of a rarity, but it typically sells for under $150 when one hits the market.
Nikon 75-150E f/3.5. This is a cult classic for good reason. While Nikon made it for the consumer market, it was embraced by studio professionals to the point that there was a call to make a Nikkor version of it. While f/3.5 isn't optimal for environmental portraiture, I find it especially useful when I take the camera "in hand" for photographing children.
Tokina 80-200mm f/2.8 manual focus, Nikon 80-200mm f/2.8D, and Nikon 70-200mm VR f/2.8G zooms. I owned these lenses in sequence. Each of them did a reasonable job for portraiture, but I really prefer a smaller lens for the task. Not only are they ergonomically more difficult to use, but on a couple of occasions I could see that my subjects were slightly intimidated "looking down the barrel" of these.
Nikon 85mm f/1.8D. I use this one when I want a fairly intimate perspective and either my subject gets a bit fidgity, or when I want to limit depth of field more than I can with the next lens on this list.
Tokina 90mm f/2.5 macro. Another cult classic, and for good reason. I actually like the "look" of shots from this lens a bit better than the 85mm Nikkor, but because so much of the focus throw is dedicated to close focusing, it's harder to obtain precise focus at portrait distances.
Nikon 105mm f/2.8 VR Micro. Obviously, I can't use this on my Nikon FA, but on the F100 it performs well enough that I haven't bought another 105mm. In the 1980's I also used the 105mm f/4 AI and 105mm f/2.8 AI-s Micro lenses, but that was more to save money than because they were nice portrait lenses.
Nikon 135mm f/2 DC. I use this lens for more formal portraits and environmental portraits. As a portrait lens, it's only real flaw is Longitudinal Chromatic Aberration when used at f/2 and f/2.8.
Nikon 180mm f/2.8D. I bought this to attempt to reproduce the more aloof look of 1950's promotional movie stills and glamour shots. Alas, I could never get the lighting quite right. The longer perspective made the shot look a bit flat, but when I tried to correct for it with split lighting I didn't like the results either. Just not my style, I guess.
So no, I don't have difficulty settling on a portrait lens for 35mm. Instead, I choose one based on the perspective I wish to achieve and a bit of sheer caprice.