Southern California's most famous Surfing Beach is Huntington Beach, called "Surf City".
There are many other beaches that are known for good surfing.
Wikipedia lists the following as the Best California Beaches for OC and LA:
Orange County, California:
Trestles, near San Clemente
The Wedge, Newport Beach
56th Street, Newport Beach
Huntington Beach, California
Salt Creek, Dana Point
T-Street, San Clemente
Brooks Street, Laguna Beach
Doheney Beach, Dana Point
Los Angeles County, California:
Lunada Bay, Palos Verdes
Haggardys, Palos Verdes
El Porto, Manhattan Beach, California
Manhattan Beach, California
Hermosa Beach, California
Surfrider Beach, by Malibu Pier
Topanga, by Malibu
Wetsand.com Surfing-oriented website.