California already has one the most encompassing definition of Domestic Partnerships - partners can sign contracts together, adopt children, inherit, see each other in hospital, make decisions about each others' health care, etc. And many companies allow partners in on their employees' health benefits.
All a 'no' on Prop. 8 would have done would be to maintain the status quo: to allow same-sex couples to keep getting Marriage licenses at the Courthouse. Today LA and Orange Counties stopped doing that. Also since CA will no longer recognize same-sex marriage, those issued in the state after the CA Supreme Court's decision several months ago to allow same-sex marriage will be considered annulled.
The No on Prop. 8 people are already mounting a court challenge to this...