All my life. When I was in high school and my Mom said to me 'All right, time to teach you how to drive,' I said, 'No thanks, I would rather not be a gas guzler, I'll stick to my bike' and so I've never gotten a driver's liscence. I just don't need nor want it. If I need to go farther than I can bike, I take the bus, or a taxi. Its compromise comfort versus nescessity for the environment in my mind.
EDIT: I might add that this was when I was living at home. My previous bike was stolen and I've been using public transit since.
Soon I'll have a new bike really soon!