I hate to see people get banned or silenced - even the people who are causing trouble. When it comes to regulations, I could almost be described as Libertarian.
Because of this I would like to make a proposal - instead of leaving the banning power in the hands of a central authority, I propose that banning be placed in the hands of the individual. I'm referring to a feature that I have seen in the Yahoo! chat forums. If you come across someone who you find to be offensive, a menace or harassing, you can individually "ban" the person so that YOU no longer see his/her posts. Everyone else will still be able to see him and his posts.
I discovered that the people who truly deserved to be banned would be banned by almost everyone within a very short period of time - and no one could ever accuse a central authority of censorship.
You end up with free speech without the annoyances.