Jim says he used to be a Jimmy. It probably won't surprise you to learn that this Tim used to be a Timmy. I can't remember when this changed from my name to the most humiliating thing that I could imagine. I did go through a brief period in college where friends of mine resurrected it and used it liberally.
I've never been a Timothy, though, not even to my parents. Exactly two people that I can think of have ever insisted on calling me Timothy: Lucie Brock-Broido and Eileen. Go figure.