Mission Beach/Pacific Beach is a good start. The surf is usually small so you won't get too hammered. If surfing is your only interest, you need not go any further.
Other options: San Diego Zoo, Seaworld, Wild Animal Park, Balboa Park, Golf everywhere, Tijuana, Ensenada, Gaslamp Quarter, Hotel Del, Rubio's, The Murph, Taylor Guitar factory, Anza Borrego, somebody stop me...