Agreed, South Bay is a wasteland if you don't have a car. I tried really hard to bike around, but even that only goes so far, especially in the summer. I'm assuming OP meant SF proper, since even Oakland is hardly walkable if you live anywhere but the downtown area.

I co-oped at IBM in south San Jose as well. My roommates also co-oped at IBM and either rode bikes like I did or had a car. We would ride our bikes to the light rail which were a little more frequent than once an hour. We also rode our bikes to the CalTrain station.

It's definitely not walkable. It's marginally bikeable. Biking was problematic because of the lack of bike lanes and the poor lighting. Light rail and CalTrain were quite accommodating to bikes.