I double barrelled my surname when I got married. Some background in case anyone is curious/this info is relevant - I love my surname and I didn't particularly like DH's (it's harsh sounding) but have come to love my two names together - they balance each other out. I also felt like I shouldn't have to give up part of my identity when I got married (I was Ms. Wander for over 30 years) so the double barrelled option seemed the way to go.
We're now expecting our first child (a boy) and I'm considering going double barrelled again - I think it would be lovely if he had both our names! But... part of me is torn. DH would then be the odd one out but I guess I would be too, if he only took his Dad's surname. I also wonder if it's fair to land a little one with such a big name! My DH's only worry is what will DS's partner do if he marries ha ha, although I reminded him he's getting a bit ahead of himself there! 
On the other hand, my husband doesn't object to our DS having both our names at all and the name we love actually goes better with maiden name so it would make sense. I'm also thinking that people will just ignore the first part of his surname anyway so I might aswell get my name in! I don't know why but people are forever ignoring my first surname e.g. so instead of Wander-Lust, I just get Lust or Mrs Lust (which really irritates me for some reason!).
Help! What did you do? Part of me wishes I hadn't changed my name and then just given our DC the double barrelled name... But as I said, I love my name now. Gahhh