As a reminder, the Perry case could have several different outcomes:
1.) The case could be dismissed if the Supreme Court finds that the Prop 8 proponents lack standing in the case.
2.) The Supreme Court could rule that statewide bans on same-sex marriage do not violate the Fourteenth Amendment's Equal Protections Clause.
3.) The Supreme Court could uphold the Ninth Circuit's limited ruling that a state cannot grant a right such as marriage and then rescind said right. This would affect California and theoretically any other state in which this has occurred.
4. The Court could rule that gays and lesbians have a fundamental right to marry and that prohibitions on same-sex marriage are inherently unconstitutional. This move would affect all fifty states, the majority of which do not currently recognize or allow same-sex marriages.
EDIT: Since the decision is expected this June, when we come closer to the deadline I'll start a poll on what people think the results will be.