Mr., Ms., and Mrs.
I think that if I were a woman, married or unmarried, I would choose to call myself Ms.. Consider the fact that a woman’s title—a part of her name—is expected to change when she gets married. A person’s name is an integral part of her/his identity; essentially our culture tells us that a woman’s identity changes when she gets married.
Contrast this with the fact that men are called Mr. regardless of marital status. A man’s identity remains constant his entire life (save for earned titles, e.g. Dr.), but a woman’s does not. Aren’t men and women equal partners in the same marriage? I think the simple answer from history is “no”. It harkens back to long tradition of inequality, typecasting woman as homemakers and treating them like property.
Why is it important that women are marked as being in the ‘possession’ of a man, but such ‘ownership’ over men is not marked? Can you a offer a good reason for this? Personally I feel that we should all maintain the same identity, married or not.