From what I understand, it is quite difficult to get in with the production houses in San Francisco. It might be wise to live in Los Angeles because there are many more companies there.
The cost of living in LA (although still outrageous compared to almost everywhere else), is much less than the cost of living in SF. You might want to keep this in mind because there are bound to be periods of unemployment throughout your career, especially if you are on the artistic end of the spectrum. I had a friend who worked in animation. In the three years that I knew her she was unemployed at least six times, and she has an extensive resume with lots of experience and contacts.