I actually like the threads, they serve a purpose... at least for me, that purpose is to check up on what other people are listening to and see what my fellow MBers musical tastes are like. Also, I use it to sometimes check out music I've never heard of before when some of my favorite posters stick songs in the threads. Does it generate much discussion? No, not really... but it's there to see what everyone else is listening to, so it does what it's supposed to.
All that said, I much prefer
http://www.musicbanter.com/general-m...above-you.html. It generate discussion, and forces people to actually listen to things other people post, especially things they normally wouldn't ever listen to. Now that I'm thinking about it, I'm probably going to bump it right now, it deserves to be at the top.