A few words about the ruling:
The district court ruling was very broad, and, if upheld, would have applied to all 50 states because of it's constitutional implications. The circuit court rejected most of that broadness and instead crafted a ruling that would only apply to CA, even if SCOTUS upheld it. In essence, the majority ruling of the 3-panel appeal said "California already gives gays/lesbians every right except the use of the ceremonial title of married. Thus, the law makes no sense and is only there out of spite, so it violates equal protection". In other places where gays/lesbians have no rights as couples, then, their bans on same-sex marriages would not fall under the same argument as this ruling. Note that SCOTUS can choose to do nothing, can review and uphold the same ruling, review and create a new ruling that still overturns prop 8, or review and reverse the circuit court and keep prop 8 as law. So this is far from over.
At least one analyst (Jeff Toobin) things SCOTUS may choose to not hear the case because of the limited scope of the ruling, choosing instead to bide time and wait until they are asked to review something of national scope instead.
The dissenting opinion ruled that gays and lesbians are not a protected class worthy of special consideration like minority races, and, furthermore, the federal courts must be very careful not to intervene over states in issues of marriage. Because the California supreme court already ruled Prop 8 constitutional, he argued that their arguments were sound, federal intervention was not necessary because gays/lesbians aren't protected, and so chose to do nothing.
Of the 3 judges, the liberal and moderate upheld the lower court ruling against prop 8, while the conservative judge voted to overturn the decision. This is going to lead to lots of 'liberal activist judges of the 9th circuit court' talking points today.
Finally, I would say that if the original ruling by the district court were upheld in it's entirety, and the Supreme court either agreed or refused to hear, we'd be looking at a legalization of polygamy pretty much immediately because the same arguments would apply-- that the state can't get in the way of consenting adults. With this narrower ruling, that is not an issue because second and third wives don't have any rights in the state right now.