I think good discussions have a lot to do with the culture of those involved. I think here on Bad Voltage we are better than most. We tend to show respect for each other and for their opinions even when we disagree strongly on a particular subject, For example, @bryanlunduke and myself have differing views on the Israel/Palestine problems which we aired in a previous topic. This does not change the fact that if we ever find ourselves in the same bar I will be happy to buy him a drink and would be surprised if he was not happy to buy me one in return.
@jonobacon actually has a lot to say on this subject and I would recommend you read his book: The Art of Community. I bought my copy but it has since been made available as a free pdf download here.