HRC has a primer on what the DOMA decision means for same-sex couples in various states:

Brian Beutler explores the implications of the SCOTUS’ decision to leave Section 2 of DOMA, “the section that says states don’t have to recognize marriages from other states,” intact:

Marriage equality supporters are understandably ecstatic that the Supreme Court has declared section three of DOMA unconstitutional. But for a subset of same-sex partners, the ruling won’t truly guarantee them equal treatment under the law. The nature of the court’s DOMA decision, combined with its decision to punt the California Prop 8 case about whether there’s a constitutional right to gay marriage, will ultimately create a sort of three-tiered status for same-sex partners. …

“As a general rule, a person who legally married a different-sex partner will be considered married in all states,” [Shannon] Minter [the legal director for the National Center for Lesbian Rights] said. “But that is not true for same-sex spouses. Many states have enacted constitutional amendments that prohibit the state from respecting the marriages of same-sex couples who validly married in another place. It is not yet clear whether same-sex spouses who live in states that do not respect their marriages will be eligible for federal benefits that turn on whether a marriage is valid where the couple or surviving spouse lives. At least in the short run, there are some federal benefits that same-sex couples in these states likely will not receive.”

Allan Brauer, who married his husband in California in 2008, explains what the ruling means for him:

The DOMA decision means that my spouse and I will now be able to file joint Federal income tax returns as well as state ones, my spouse will no longer pay Federal taxes on the value of my health insurance, and the tragedy of losing a spouse will no longer be exacerbated by unequal treatment of our estate and Social Security benefits. Hooray!

But… If we were to relocate to a state that does not permit SSM or recognize such marriages performed elsewhere, some of those Federal benefits may simply disappear. Poof! Current Federal regulations vary across departments in whether they look at your legal status based on where you live, or where your marriage was performed.

Linda Beale predicts more litigation in the near future:

[T]here is a huge problem looming because of the failure of many states to recognize same-sex marriages performed in other states even though they recognize all other marriages performed in those other states. Section 2 of DOMA–which allows states to refuse to recognize sister-state marriages–in flagrant violation of the normal rules of comity between states–was not at stake here and thus its repeal remains for future cases. This means that there will be considerable uncertainty –and much bigotry and discrimination against gay couples for some time as those states that have enacted discriminatory constitutional or statutory provisions against gays continue to deny marriage rights to gay married couples when they move into them, and perhaps prevent them from retaining custody of their children or being able to legally divorce their spouses or will estates to their spouses.

These problems will be resolved, at least for now, under each states “conflict of laws” provisions, with the overlay of the state’s constitutional prohibitions, where existing, on recognition of same-sex marriages. This will cause harmful suffering to gay couples, so one would expect that there will be litigation on this issue soon.