At least in the US, it really should be a state-level issue. It's not a matter of "civil rights," totally incomparable to the racial inequality of the greater part of the US' history, so local-level decisions on the matter are entirely appropriate; they're the communitites bearing the burden or receiving the benefit of any public policy they make, and thus should not have a policy (whether pro-gay or anti-gay) forced upon them.

As a personal preference, I believe there are issues of MUCH greater import in the world and which deserve the undivided attention of the US and world community before we worry about relatively petty matters -- the issue of gay marriage must needs pale when juxtaposed with northern Uganda, Darfur, September 11, etc.