IFAIK domestic partners have the same rights under California law as married people do. So the marriage decision is moot. I think that government should get out of the marriage business altogether and just adjudicate domestic partnership rights. In other words, you go to the state to get a domestic partnership license which will grant the partners certain rights and responsibilities under the law regardless of the genders of the respective partners. Marriage, on the other hand, is a religious/social ritual/agreement like, say, baptism and as such is irrelevant to the state and separate from it, like religion itself.
But if I were a gay in California (I am neither), I wouldn't be so quick to pop open the champagne. It won't be long until some right-wing stormtroopers start a movement to draft an amendment to the California constitution forbidding same-sex marriages. It's already happened in several other states. Sad. Sad and evil.