So I'm on campus this summer. I brought my car from the East Coast and I think it was a very good decision to make. Basically, Stanford is liveable without a car, but the hassle is immense. You make up a lot of the gas money in savings on groceries for instance (look up the Milk Pail Market in Mtn View for a cheap place to get amazing produce). Otherwise you have to shop at JJ&F and Safeway (for the former, can you say $5 gallons of milk?). In terms of traveling around the Bay Area, you do not need a car to go to San Francisco or San Jose, even though it's much faster if you drive. You also don't need a car to get to and from either SFO or SJC. But if you want to travel anywhere else in the Bay Area (i.e. Berkeley), I think having a car is a necessity. It depends on how much you see yourself traveling at weekends I suppose. Of course, there is always the zipcar option for that, but do be careful when factoring in all the costs.