Howling:The Wedding of River Song speculation

As we know it, the last episode of Series 6 will be entitled "The Wedding of River Song". Here's the one million dollar question : who is she marrying ?

The first answer that pops into anyone's head is "the Doctor", but it would be too expected... though I'd like to see the Doctor as a Groom, and I'd really like to see the tenth Doctor invited as a guest (as he said once : "I'm rubbish at weddings, especially my own" : maybe he was referring to this one)

Or maybe it will be a metaphorical wedding (as Idris was a metaphorical wife to the Doctor...