Here's the way I see it. (And yes, I know that strictly speaking a troll is a post and not a poster, but "troller" sounds weird to me, so I'll just say "troll" for both and trust that my meaning is clear.)
Trolls are useless. Their only purpose is to be disruptive. If you rise to the bait, you ensure that they achieve their goals. If you can make a silk purse -- a meaningful discussion about pedophilia, for instance -- out of the sow's ear that is a hit-and-run troll, then by all means do so. However, by engaging the troll itself, all you're doing is giving it incentive to stick around. We've already lost one terrific eplayan because he couldn't tolerate the troll issue that's splattered everywhere.
By engaging the trolls at all, you encourage them to stay. They feed on flames. Every response Mr. Hat gets will just encourage him to flood the board with four or five more silly threads. Do you really want that?
Personally, I'd rather not have the bastards around at all. I'm a nerd, and I've spent entirely too much time on BBSs in my day, and I can say with all confidence that trolls are the same everywhere. They never do anyone any good. In the absence of moderation, the only recourse we have is to make sure that this environment is inhospitable.
Beating up on trolls may be momentarily satisfying, but I can guaran-goddamn-tee that it won't be worth it in the long run.
Won't somebody please think of the children?!