Banning is good and all. But if I was to be banned, I'll just take a week off, then come back, act like nothing happened and do all the same things that I used to do again.
You see - Rep power is all they have over all the other posters. One of the things I don't like is members with high Rep count neg-repping new posters just as a bullying tactic. Nobody wants to stand up or say bad things about these guys because they're afraid of getting neg-repped.
What I would do is straight away decrease Rep power by say 5. I'm pretty sure they'll stop what they were doing before and start acting like civilized people.