In my opinion, the best places for kids/families in San Francisco are the Haight and its close neighbor, the Inner Sunset. Housing is resonably priced (for SF), it has a small town feel, the streets are ecclectic, but still mostly safe, and they both border Golden Gate Park. The weather is not good in the Inner Sunset, there is more fog their than anywhere else in the Bay. Beaches and the zoo are relatively close to both neighborhoods. Take the Muni bus ($1 for 4 hours ?) straight down Haight with your child (how old?) to the Metreon, Yerba Buena Center for the Arts (very kid friendly), SF MOMA, the Aquarium (Fisherman's Warf), or the Exploratorium (a science center for kids in the Presidio). I love SF Bay Area, there are so many good things that I could say about it. Above is just for SF, get out of the city and there are just endless things to do. Culture, nature, great music scene, it has it all!
My mom always raves about how great it was to grow up in my hometown of Haverhill, Mass. Close to the beach and mountains, can walk to school, and just a great city. It's kind of gotten bad lately, just because the high school sucks, but I want to raise my future family in somewhere like Newburyport, Mass. Growing up in Georgia isn't too bad but just way too conservative. I have probably one of the best public school systems in the country at my disposal though and probably have a better education than most private school kids and definatly than homeschooled kids, so that makes me happy. Isn't much to do here though and too many religious whackjobs running around telling people that they're going to hell.