Another vote for the Nikkor-S 50f1.4... If your FM3a is a chrome body, the chrome barrel of the 50f1.4 will provide the "look". It also performs pretty well, in my experience. The single coated glass seems to have more contrast than the first multicoated version, that being the Nikkor-SC 50f1.4, and seems to provide the same contrast as the AI version. I have two of these lenses. One with the factory AI modification done, and one that's still non-AI.
-J