Pioneer Woman has an entry today that made me think hard about who I am. You can go over there and read the whole thing, but it boils down to what she asks her readers to do: "What are your five adjectives? How would you answer, with a list of five items, the question “WHO ARE YOU?” Go ahead and scrape the depths of your psyche. You need to let it out."
What she's saying is, use five adjectives (or nouns) that describe you.
Check out the hundreds of comments there, and notice how many people use their relationships to describe themselves. "Wife, mother, sister, friend...". Somehow that doesn't tell me the essence of a person. Or does it?
Food for thought.