Austin has a lot of sprawl, commuting satisfaction will vary greatly depending on where you are. But if you work and live in downtown, you should be good. I'm up north and you really have to want to commute to make it work.
As for needing a car, there's a Whole Foods (I always think grocery store locations are a good indicator of commute-ability) down there along with most other things you would want, so maybe you could be car-less?