I agree with sonjad about Berkeley. I've lived here for two years without a car. We have ZipCar and City Car Share for short trips, and there are tons of rental places for longer trips. At UC Berkeley students get a "free" bus pass for AC Transit... actually, the fee is built into tuition/fees, but it's very small. AC Transit is really reliable, safe, clean (mostly), and covers most of the area, including Transbay service to San Francisco. There's always the Bart, too, which is great. We also have a complete network of Bicycle Boulevards, streets designed with bicycle lanes and traffic calming devices, so it's easy to bike to the grocery store or campus.
Off-street parking is pretty expensive in Berkeley, and on-street parking isn't always easy to find or that safe. My neighborhood in particular has a lot of auto thefts each week. That's just one more reason not to have a car in Berkeley!