Marin County has some of the best public schools in California and they're only getting better. Parents continue to be involved, pushing for smaller classroom sizes, expanding programs and volunteering, while the general public repeatedly votes to pass any bond measure that creates more money for local schools. In short, Marin is a community with a heightened awareness of the quality of education, continually striving to improve an already great school system. For the last twenty years, I've read these types of headlines in our local papers:

Residents with or without children are aware that this is a hot button in today's real estate environment that can directly effect housing values, and they're right.  Forbes Magazine (Summer 2008) in their article called "America's Best Place to Raise a Family" said, "Because of an outstanding school system and abundant employment, Marin County cracked the top twenty for California.  They went on to say:

        "Marin County offers the best education in the country,
    with a 97% graduation rate and a list-topping average
    SAT score of 1,133" 

Today's home buyers often make their decision to buy in Marin based on the quality of the education here, not because houses are cheap and affordable.  Where you generally get less house here than other counties, you are rewarded with a much better educational system from start to finish.