I grew up in a family that didn't have a car. Luckily we live in Toronto, so public transit has always been available and affordable. I don't even have a driver's license (although I contemplate getting one all the time). Last year I decided to spend the summer riding my bike and limiting the amount of bus time. It went well, so this year I have given up my bus pass and ride my bike every for fun, errands, fun, work, fun, seeing friends, and fun. I'm hoping my bus pass less existence will last far into the winter!
Most of my commutes are brief, maybe 8 to 10 km round trip. The only errand I walk to is the laundromat. The laundry fits in a large four wheeled shopping cart that I walk only 2 or so km round trip (even in winter it isn't bad since I walk down a well plowed main street).
I'd like to buy a trailer, but my apartment is tiny (and so is the elevator). So far I am using a combination of panniers, handlebar basket, and back packs to haul my stuff around town.
Hopefully I will do this forever!