One of the stand-out moments for me (apart from the whole marrying-the-guy-I-love bit which was incredible) was that we had a friend of my mother's drive up from the States to play the harp at our ceremony, and at my request she played Robby Burns' 'My love is a red rose' while we were signing the marriage license. The surprise was that my father sang the song. I didn't expect that. Luckily they did that during the rehearsal so that I wasn't completely taken by surprise during the ceremony itself.
It was a small wedding so I got to talk with all my guests. 
Like anyone notes, months of planning and over in a flash. Now onto the real challenge - marriage!