San Francisco is amazing; I've loved the time I've spent there. It is expensive, but it's really beautiful and there's tons to do.
I got to spend a week in Austin this winter, and I LOVED it, but we were down on Sixth Street, so I didn't see much of the 'day to day' areas of the city. It was fun, though, and I liked almost everyone I met. My boyfriend was a little skeptical about visiting Texas for that long, because the couple times he's been there he has had some issues with racists, but he didn't encounter any of that in Austin. The live music was great.