My answer doesn't quite fit the poll: I tell one or two very close friends, and sometimes will share online, like on this group. But we don't share with family ever, or general acquaintances. Like you, CookAMH, I really enjoy the big announcement. I always think it's kind of a letdown when other babies are born and I already know everything about the kid except the weight. I've really enjoyed not knowing the sex in the past, but I'm having fun knowing this one time too. It's a different kind of fun, but it's been exciting, especially since it's different for a change! I'm sure it will take some of the excitement out of the announcement, but we'll still have the name.
The other reason for not telling is because I don't want to hear negative opinions! It's hard enough to agree on a name as a couple. I don't need my sister's inevitable disapproval. Or my mother's "Hmmm... I'm not sure about that name...". We had that happen last time when I happened to mention to her that we were considering Jack. She didn't like it. In the end, not a big deal as it was not top of my list and I wasn't attached, but I'd hate to have that happen to THE name, you know? Once the baby is born and the name is official, it seems people are more polite about their opinions.
As it is, the two friends I HAVE discussed names with both prefer others on my list of first names to the one we may have chosen. They didn't express dislike of it, per se, but they definitely liked and commented on others and didn't have much to say about this one. Oh, well. At least they're polite!