Wow, this is a fascinating thread!
I have always gone by Elizabeth, except for two years when my brother David was very small. He called me "Betty", and the rest of the family did, too, until he learned to say "Elizabeth". Nobody else called me "Betty". I like my full name. My husband, also a David, gets "Dave" from a lot of people, sometimes even his family, but I always call him David. Another David I know told me he liked that I didn't call him "Dave" like everyone else.
For several years I was known by a totally different name to a lot of my friends. I was part of the Society for Creative Anachronism, a mediaeval recreationist group. Part of that is to create a mediaeval persona for yourself, with a different name from your "mundane" one. Mine was Searu, adapted from the OE word for "skill, craft or cunning". There are people to this day who do not know my given name. The boyfriend I had at the time (yet another David, is there no end to them!!??) never called me Elizabeth, and did not permit me to call him David. We used only our SCA names. (We notice that this relationship is long, long over!)
In my religion people frequently use names which are different from their given ones. There are, again, people who don't actually know my given name, but who know me by my other name.
As for our names being all that is left, I think it has actually been quite the opposite for most people. Even people who have left works of art have not always left their names - the Housebook Master, the Master ES, the Master of Mary of Burgundy (named for a book of hours he - or she - illuminated) and many, many more recorded simply as "Anonymous".
I changed my name the first time I got married, and Elizabeth Creith disappeared. This Mrs. Daniel Zlatin chick was everywhere. I felt invisible. I changed back. I never, ever called myself by my husband's first name (Daniel is an odd name for a woman) but everybody else seemed to think that's what I should be/wanted to be called.
