"We do not celebrate when two people merge their bank accounts; we celebrate when a couple marries." ~page 39
"The court found, among other things, that (1) marriage benefits society by organizing individuals into cohesive family units, developing a realm of liberty for intimacy and free decision making, creating stable households, legitimating children, assigning individuals to care for one another, and facilitating property ownership; (2) marriage benefits spouses and their children physically, psychologically, and economically, whether the spouses are of the same or opposite sexes; (3) domestic partnerships lack the social meaning associated with marriage; (4) permitting same-sex couple to marry would not affect the number or stability of opposite-sex marriages; (5) the children of same-sex couples benefit when their parents marry, and they fare just as well as children raised by opposite-sex parents; (6) Proposition 8 stigmatizes same-sex couples as having relationships inferior to those of opposite-sex couples; (7) Proposition 8 eliminated same-sex couples' right to marry but did not affect any other substantive right they enjoyed; and (8) the campaign in favor of Proposition 8 relied upon stereotypes and unfounded fears about gays and lesbians." ~page 18
"A law that has no practical effect except to strip one group of the right to use a state-authorized and socially meaningful designation is all the more 'unprecedented' and 'unusual' than a law that imposes broader changes, and raises an even stronger 'inference that the disadvantage imposed is born of animosity toward the class of persons affected.'" ~page 46
"A preference for the way things were before same-sex couples were allowed to marry, without any identifiable good that a return to the past would produce, amounts to an impermissible preference against same-sex couples themselves, as well as their families." ~pages 71-72
"By emphasizing Proposition 8's limited effect, we do not mean to minimize the harm that this change in the law caused to same-sex couples and their families. To the contrary, we emphasize the extraordinary significance of the official designation of 'marriage.' That designation is important because 'marriage' is the name that society gives to the relationship that matters most between two adults. A rose by any other name may smell as sweet, but to the couple desiring to enter into a committed lifelong relationship, a marriage by the name of 'registered domestic partnership' does not." ~page 37
"In order to explain how rescinding access to the designation of 'marriage' is rationally related to the State's interest in responsible procreation, Proponents would have had to argue that opposite-sex couples were more likely to procreate accidentally or irresponsibly when same-sex couples were allowed access to the designation of 'marriage.' We are aware of no basis on which this argument would be even conceivably plausible. There is not rational reason to think that taking away the designation of 'marriage' from same-sex couples would advance the goal of encouraging California's opposite-sex couples to procreate more responsibly." ~page 60
"All that Proposition 8 accomplished was to take away from same-sex couples the right to be granted marriage licenses and thus legally to use the designation of 'marriage,' which symbolizes state legitimization and societal recognition of their committed relationship. Proposition 8 serves no purpose, and has no effect, other than to lessen the status and human dignity of gays and lesbians in California, and to officially reclassify their relationships and families as inferior to those of opposite-sex couples. The Constitution simply does not allow for 'laws of this sort.'" ~page 5
You can read the full majority opinion here.