I live in NYC - we've never owned a car in the city. I take public transportation or walk for every journey in the city, along with occasional rentals for vacations or the occasional cab/car service for early starts or late night journeys home.

I can't even imagine owning a car here - there's nowhere to park on the street and even if you can find a spot you have to move it on a regular basis and garages are very expensive. Add to that horrid traffic and crumbling roads, it's just not worth the stress.