I was struggling over this list until I realized the question was my favorite and not the best years for film. I went through a list of my favorite movies and the seventies came out on top. I think the forties might have been a better year for film, but I am Woody allen nut so it was either the seventies or eighties for me.
1) The Godfather 1 1972
2) The Godfather 2 1974
3) One Flew Over the Cuckoos nest 1975
4) Manhattan 1979
5) China Town 1974
6) Taxi Driver 1976
7) Annie Hall 1977
8) Play it Again Sam 1972
9) Clockwork Orange 1971
10) Apocalypse Now 1979
For What it's Worth
1) The Godfather 1 1972
2) The Godfather 2 1974
3) One Flew Over the Cuckoos nest 1975
4) Manhattan 1979
5) China Town 1974
6) Taxi Driver 1976
7) Annie Hall 1977
8) Play it Again Sam 1972
9) Clockwork Orange 1971
10) Apocalypse Now 1979
For What it's Worth