Noise, for instance, thinks Creative Commons does more harm than good. Since i respect her views a lot, we had a long discussion about it (until something like 5:30 in the morning). I live for these kinds of conversations. I learned a lot and i think we were able to pin down some of the ways we differed, and i tried to summarize it all on page of opposing views on Creative Commons.
This is a really interesting issue to me. What do you think? Have a look at the summary and post your opinions here.
Update: this discussion has now been mentioned on Lessig's blog. I'm looking forward to what he has to say.