Santa Cruz Beach Boardwalk: one of the last great oceanside amusement parks. If you're looking for some good food in that area, try Phil's Fish Market in Moss Landing (local favorite/hole in the wall but featured on Throwdown with Bobby Flay) or any of a number of restaurants at Capitola Beach (great place to walk around/people watch). Monterrey and Carmel are also really nice, Monterrey Bay Aquarium is one of the finest in the world.
I have plenty more recommendations for the San Francisco/Silicon Valley/Monterrey area if you'd like them. And it would help to know what you would like to do.
I also have (less) knowledge about the LA area.