Question though, is there a danger that 'discussing' marriage in a couple could be misinterpreted as a proposal? I've never been near the situation, so I wouldnt know. But it would suck to have your romantic proposal taken away.
I've never been near the situation, either (good way to put it), but I'm sure there have been many couples where one person was more eager to get married than the other, and took any discussion of the subject (or even mention of someone else
's marriage) as a confirmation that the other person intended to marry them. And when couples get out of sync like that, it can lead to some very sticky situations.
I know couples who have discussed marriage, agreed to everything, shopped for the ring together even, but don't consider themselves actually ENGAGED until someone does a formal proposal and presents the ring. So you can have both the pragmatic discussion and the romantic proposal.
Personally, if we discussed the subject and agreed we were getting married in the near future and started taking steps towards that, I would consider myself engaged, and wouldn't need (or even want) an official "moment." So I wouldn't have a cute proposal story to tell people, but that's okay with me, because I don't consider that personally important. To each their own.