One thing that might not obvious to people moving here is most of silicon valley is very suburban, and if you work in the south bay, most of your coworkers are going to be married with families in their 30s at the very least. Even in the startups. If your single, try to live and work in SF proper. Far more of your coworkers will be in your age range and the gender ratio will be somewhat more balanced. The commute from SF to the South Bay is a frustrating hour minimum.

Rent wise, SF and Palo Alto have about the same rent, even though half of Palo Alto and Mountain View is 1930s craftsman track houses.