I'm usually pretty reserved on forums. If I get into long discussions, it's usually a rant or argument. In addition, there have already been threads asking about encouraging thread creation.
So how about this: keep the 3000 post count for a title bar (though I still think that's high), but also count posts that are in response to your created threads. Yes, that means posts will be double-counted for different users, but I'd much rather take the time to make interesting threads than try to knock out 3000 posts relatively quickly.