Hey all right, I was born in SF and have lived in the Bay Area my whole life.
You definitely got to check out the SF beach, great place for bonfires. Also take a visit to the Haight-Ashbury, Golden Gate Park (bigger than NYC's Central Park), the Chinatown/North Beach neighborhoods (including the Church of Scientology right across the street from the Transamerica Pyramid) and of course the Golden Gate Bridge. And you might as well check out the Castro district, just to see if it's as crazy as the internet say it is (seriously though, the Castro Theater is frickin beautiful and plays great movies).