I'd add Chicago as well. I've lived here for 5 years (always without a car) and it's never been an issue; though I'm always amazed how many people living in this city do have a car. $85/mo for an unlimited cta pass is so much cheaper than car+parking+insurance+gas+repairs...
I never really feel like I'm missing out by not having a car. Like impolyt said its so nice to be able to go out drinking and not have to worry about driving home or getting a DD; actually, I hate when I go to a party with someone that does have a car as inevitably you end up spending 30min+ going around in circles with them while they look for a spot to park.
Also, for anyone that lives in a major city you can always just use zipcar for the rare occasions you need a car.