Now that I think about it, I think "Ed Wood" was black and white, along with a low budget western Johnny Depp did some years back. "Clerks" was also shot in Black and White for cost reasons.
Plus, there's the most recent one I can think of: "Nebraska". Before that, there was "Melancholia".
"Sin City" used black and white with periodic use of color for emphasis to give it a graphic novel feel.
Of course, I can't believe I forgot "Raging Bull" and "Doctor Strangelove".
Woody Allen shot "Manhattan" in black and white because it's how he remembers it via photographs from when he was younger.
However, there's one movie that is the finest example of shooting in black and white in a post color world: "Psycho".
As I started thinking of the above films, I decided to do a search to see what films were made in black and white after color film was available. I found this list:
List of Black and White Films Produced Since 1970
The gist of the above link is that color workflow was fully established by that point and everything was shot in color unless there was a specific reason. The transition period had ended, so availability of equipment or studio policies were no longer a deciding factor so much as cost or artistic intent.
In short, I don't think we can really say for sure just how many movies would have been shot in color even if color film had been available at the time. Some directors might have made the same choice in stock because they felt the subject matter warranted it.
Those gangster flicks from the 20's and 30's might not have looked nearly as gritty in technicolor. I can't imagine James Cagney firing a zip gun or calling someone a rat in color.
Edit: I should say, though, that Ray Harryhausen has said he doesn't mind having his movies colorized because he stands by the idea that he would have shot in color if he had the budget. Of course, since there's no way to ask many of the black and white era directors what they would have done or would want now, we should probably error on the side of leaving things as they were made.
Edited by NetworkTV - 2/27/14 at 12:33pm