I think a lot of it depends on how you look at marriage, if you look at it from the love perspective then of course. Religion has no claim to ownership of love.
Also, the catholic church's own teaching is contradictory in the sense that they teach the sacrament comes from within ie. it is the people who marry themselves. That's the way it was done thousand of years ago. People married themselves if they were that much in love. No God, no bible, no BS.
But I can see where people like Deestruction come from too when you look at how most marriages are.
Also at the risk of being cynical and controversial, these days marriage is really just another way for governments to control society. Once you have the spouse and the kids your life revolves around them, you are distracted. The greatest threat to a government has pretty much always been the masses of young single males. I'm not being sexist in saying that, but women haven't had a voice really until recently and of course they are just as loud these days. So I would hate for all our valiant Queens to grow timid.
If you look at it from an equality perspective, then no question it's a yes.
Religious stance? Marriage is not religious, they have no argument.
I'll definitely be interested to see what the numbers are like for gay marriage in the coming years considering the overall numbers are decreasing and the abysmal divorce rate.