This has made interesting reading - it's cheering to see that others do think carefully about this issue; I also have various female friends, some of whom have kept their name on marriage but all of whom have named their child after their DH.
Having said that, I've done the same but for rather different reasons than most. I got pregnant by accident fairly early in our relationship when we weren't even living together, so we were discussing all kinds of decisions at the same time, like whether to move in together, where and how to live, DS' surname, etc etc. DH (we've since married and yes I kept my name) compromised on a number of important points for me, including that our household and DS would be vegetarian, even though he eats meat (and of course continues to do so outside the home).
We then discussed the surname point, I was all for flipping a coin as it was the only way I could see that was fair, but he thought it was a flippant (hehe) way to decide. We didn't argue about it, but just couldn't decide as it was important to both of us. In the end, I decided without pressure from him to offer to give it his surname - my rationale was that I couldn't have everything my way, and the vegetarian thing was at least as important to me. DS has got my surname as a second middle name however, so it's in there (we couldn't really double barrel as it was a really stupid combination!). I don't regret it, although I do get irritated having to explain to the doctors etc that we have different surnames.
I would welcome your (constructive!) thoughts on the following however: we're now expecting DC2. I haven't raised this at all with DH as yet, but I'm wondering about suggesting that it's fair for a second child to have my name, or alternatively, that if it's a girl, it should have my name or his if it's a boy. I think that would be fair, but my only reservation is whether it would be strange and annoying for the two DCs to have different surnames, e.g. constantly having to explaing to people at school in years to come that yes they are related, and no they don't have different fathers? What do you think?