Charles Krauthammer offers up an "I told you so." He also has this observation on the argument that gay marriage is going to destroy traditional marriage:

I'm not one of those who see gay marriage or polygamy as a threat to, or assault on, traditional marriage. The assault came from within. Marriage has needed no help in managing its own long, slow suicide, thank you. Astronomical rates of divorce and of single parenthood (the deliberate creation of fatherless families) existed before there was a single gay marriage or any talk of sanctioning polygamy. The minting of these new forms of marriage is a symptom of our culture's contemporary radical individualism -- as is the decline of traditional marriage -- and not its cause.

I've heard that the acceptance and/or legalization of gay marriage will open a floodgate of other non-traditional unions: adult/child (ala NAMBLA), human/animal, etc. We live in interesting times.