I may not be a fan of living in LA but while going to school here I make the best of it by surfing as often as possible. As for the Asshole statement, in my travels around the country, they exist everywhere!
Unless your at some little surf beach where some little punk and his friends have staked their claim, Surfing Etiquette and a little bit of skill is the same as river Etiquette and skill. If you cut someone off or don't pay attention then you deserve to get barked at, but if you are out there to enjoy the water and can do it with some skill then the boarders respect that and share.
This is the start of my 3rd year out here, so far I have only had one neg experance and that was in San diego County. I'm surfing somewhere from Santa Barbara to the OC at least once a week. Just come to surf.
So as to the where question. Where are you staying? LA, OC, San D. Are you camping or hoteling it... If this is a raod trip out of the car then San O mentioned earlier is sweet for the camp and surf, but it's hours from LA.
There are lots of options and I req checking the weather reports to see if there is a storm throwing its blessings at us. Storm south means hit the south facing beaches etc.
Enough for now, Email me with your dates and I can make some more suggestions.