Except for my last year of high school, after my bike had been stolen and I didn't care because I had a driver's license, I've used my bike for at least some of my transportation.
Living in the city the last two years, I've been riding my bike to school except when it's icy, and using a bike for short trips that are too far to walk, and sometimes for longer trips.
I'd love to get rid of our family's car altogether, but, especially during the winter, my wife isn't really willing to bike more than a few miles, and it seems things would be a bit difficult with children, especially as public transportation isn't great in this area.