What are the wedding guests you've been most excited to see turn up at your ceremony? I always get married too soon, and as such haven't completed enough quests to have enough guests show up to my weddings. Personally, having Mjoll and Kharjo show up for several of mine was a nice touch.
Also, have anyone ever had Serana and/or her mother show up to theirs? Been very curious about it, but hasn't happened on any of my saves where I've waited until the end of the Dawnguard MQ to get married.