It's a complex thing and you have been given some good advice. If you swing with the FM2, the 85 is a nice piece of glass, I would mate it with the 35mm 2.0 AI lens, not the 50mm.
In my world, if I want what I use to shoot 35mm with, I normally now grab the GF's digital (I don't own one myself). The FM2 sits in the cupboard most of the time. To be honest, her Olympus digi takes as good a photo as my Nikon does or better.
If I am going out for serious work, the MF stuff comes out, my Mamiya 645 handles just about as well as a 35mm with better results. When I get very serious, the rb67 and tripod are summoned. Sometimes I pull out the C220 and shoot square. And when I get in that crazy, go make art mood, the 8x10 is prepped and ready to shoot (B&W only).
So lots of thoughts. If I were you? If you really want to shoot film, get the Nikon set up with those two lens. They will take you a long long way.
tim in san jose