Mountain View is a pretty walkable and bike-able little town, more than I expected, even. I rarely miss having a car, and I certainly don't miss the hassles that come with having a car: Insurance, registration, etc. And, let me tell you...insurance on a two-seater sports car, for a male driver, under 35, with a handful of speeding tickets, is not a trivial consideration. I paid nearly as much to drive my car as I did to live in my house in Austin, and since living in a house here in the valley costs twice as much as in Austin, it all evens out pretty...umm...evenly.
I enjoy biking and walking quite a lot, and they're certainly healthier activities than driving for myself and the world, so I think it's a really good trade. I think it'd be an even better trade in SF, but it'll probably be another year before I head up that way. I like the lack of distraction in Mountain View while getting the company off the ground.
I think California is getting to me, because I'm also thinking the Altima hybrid looks pretty swish.