There are a ton of legal ramifications, including tax benefits (it's advantageous for a married couple to file income taxes jointly), immigration (spousal visas etc.), inheritance, and so on.
I believe immigration and federal taxes, which are handled solely by the federal government, are not affected as the US (on a national level) already recognized same-sex marriages after the DOMA overrule.
https://en.wikipedia.org/wiki/Rights_and_responsibilities_of...