In an effort to improve the signal-to-noise ratio in the Prop 8 comment threads, here is a link to comments by a California law prof posted shortly after the election. A couple of key paragraphs:
Note that Prop 8 does not affect registered domestic partnerships. It also does not affect antidiscrimination laws (Unruh) which prohibit discrimination on the basis of sexual orientation. It very likely does not even affect the Marriage Cases ruling that sexual orientation is a protected category (except as to the specific application to marriage).
Registered domestic partner gives all of the legal rights as marriage, on a state level. Marriage is restricted by federal law, so on a federal level, marriage will be man/woman, regardless of what a state says.