From The Accidental Genealogist: "Do you share a first name with one of your female ancestors? Perhaps you were named for your great-grandmother, or your name follows a particular naming pattern. If not, then list the most unique or unusual female first name you've come across in your family tree."
My maternal great-great grandmother was Sarah Drexel Fell Van Rensselaer (1860-1929). Her granddaughter, my great-aunt, was Sarah Drexel Henry (1905-1977), called "Sally."
My mother told me that Aunt Sally always thought I was named after her. I don't think I was named after either Sarah, but my mother never told Aunt Sally that -- I think my parents just liked the name. It's odd really, I don't think of myself as having a family first name -- unless I have a reason to think about my name -- like now.