Also....the typical trade off in many large cities..including silcon valley/san jose area.....the farther you live from the job center the cheaper it usually is but then the commuting time is longer and public transportation will be minimal.
As the other poster said there is various differences in living costs based on city. Another big driver in housing costs is living in a very good school district.
Because of commuting time manty of the highways and main road ways will have what is called HOV or HOT lanes...
HOV =high occupancy vehicle which will say if its 2+ people requires. HOt is for 2+ people but if you are one person you pay a toll to drive in that lane.
http://www.dot.ca.gov/hq/traffops/sy...Cal_Sept11.pdf
To save money if you live 20 miles away from your job and you and your wife can work in the same area then you can drive to work much faster than if you were driving alone.
For day care for kids keep it close to work. A great bemefit is some companies offer on site daycare for employees.
If your employer is large and its in a large employment area you will see the closer you try to get to your employer for drive time the higher the cost to live there will be. For example you may need to pay $2000+ close but only $1300 far but the trade off is you will be paying more for gas and time driving.