I like plastic.com.

It's a great place to get good debate from people who are actually educated to the issues that they speak of. Also, since it works on the slash-dot model (group moderated), morons tend to be scarce. That doesn't mean, however, that valid viewpoints that people don't like are removed, more that viewpoints that are ad-hominem or aren't based in documented fact generally get savaged out of the discussion.