Wow this has generated a lot of discussion!
DP and i have discussed getting married eventually, when we feel reday rather than because we have a child. Whether I would change my surname I'm not certain about - much of a pain as mine is I'm so uaed to it! Though I do like the idea of us all having the same surname. I friend of mine who alreday has a double-barrelled surname changed hers, her partners names to a toatlly new surname which they also gave their baby - it was a big hassle but I guess she had a point when she said 'why should one partner lump all the hassle of changing their name?"
I forgot who mentioned the use of maiden name as middle name in the US but it sounds like what they do in Chile: My sister lives there & she was explaining to me how every child has both their mother's and father's surname and when a woman gtes married she drops on eof them and picks up her husbands - quite a neat idea I reckon....though it could just as easliy be the guy who changes his name in my opinion!