Hi Modulus,
Picking this up from your post, even though it was months ago ...
dwise1, Wounded King and Sylas spring to mind. Many of RAZDs posts are the way I described - but sometimes he runs afoul of the excessive quotes/links heuristic.
I think one of my faults is to try to answer all the questions in one post, which then increases in size in the next round as more points are added in response.
If I could point to one thing - it would be always give the impression that you take your opponent seriously, if you want to have a serious discussion. While you may think it merited, if you are going to 'effectiveness', mockery (even if you aren't intending to be taken seriously) can really undermine that goal.
Indeed, respecting the other opinion/s goes a long way to ensuring that your reply is not just a brush-off.
If I could police myself I would say take one point to respond to -- the one you think is most questionable, and say that you can take up the others once this is resolved.
Label your reply with the point you want to cover (ideally this creates a subthread focusing on this point)
Then quote the point, rephrase it to ensure you understand it, say why you think it is questionable, and then cite backup links/information.
If there are other points you want to cover you can repeat this process in a new post, but then you risk having the post you are most interested in ignored in favor of the second post.
For instance, if someone espouses a YECetism, one could start by arguing that the age of the earth is shown by objective empirical evidence to be 4.55 billion years old.
Enjoy.