Hey TIS - the type of troublemakers you're talking about - all they want is for you and everyone else to reply. They want the attention. It doesnt matter what you say to them, they just want you to respond. That's their bread and water. And when you dont give it to them, they usually lose interest and dont come back. So ignoring IS the best and easiest option.
If you fight back and tell them "where to go" - that will only make them stay here and maintain their crap. That's why by lashing out, you basically show that they exist for you, and that gives them motivation to stick around.

They wont bother writing their crap if nobody responds to it.

Anyway, that's just my opinion. I'll be back in half an hour to write more about the whole topic.