I have been licensed to drive since my teens (currently early 30s). I used to own a car, which I bought used on CL. It eventually died, and I decided to see if I could live without it. I mostly rely on my bike or walking, occasionally use public transit, and have a zipcar membership. I do not live in a super walkable area or have access to fantastic public transit (we have a few bus lines, forget about big city amenities like a metro/subway). If I want to go away somewhere (say, camping), I will usually carpool with a friend who does own a car, and give them money for the gas. Or I take the train, if that is an option.
Right now, it works well. I don't know how well it would work if I had kids or a more demanding job (or both). I probably do spend an average of 2-3 hours each week extra in transit that I would not spend in transit if I were driving. Most of that is on the bike though, so I count it as less time I have to spend working out. So I don't know if I will buy a car again in the future. If I do have kids, I probably will try to facilitate their learning to drive early on, as I think in the US it is just one of those skills that is good to have, even if you rarely put it to use. If I were living somewhere with a longer history of public transit (i.e., Europe) I might be less inclined to think it was important.