Mystery solved. Not being able to remember the name of that revival movie house in New York with the AB, BC, CD... programming was driving me crazy, so I polled my New York friends and one of them came through:
It was the Regency, but not as far north as you remember, it was at 68th just two blocks north of Lincoln Center. They replaced it with an apartment building in the late 80s with a noodle restaurant at street level. The guys in charge of the programming tried to continue it at a couple of other locations, W. 57th, E. 23rd, and never succeeded.
Video killed them all -- the Carnegie (now the new Zankel Hall, I haven't been there yet), the Bleecker, the Theatre 80 St. Marks (now the Pearl Repertory Theater, haven't been there either). I get to the Film Forum every once in a while, but it's tiny.