My San Diego perspective: Sushi on the Rock, La Jolla. I have tried at least a dozen of the "best" sushi joints in San Diego and have pretty much stopped going to all of them in favor of SOTR. Thei fish is always the tastiest and freshest. The have the traditional dishes and lots of great "California style" rolls and the like. They also have the best and most creative vegetarian sushi I have ever tried.
My vote in OC goes for Taiko. Much more traditional than SOTR but excellent as well.