I would absolutely love to recommend the comm I'm in to you, though I don't know if you would want to take a look at it. It's called
visualmusic, and it caters to musicians only. It's a small private comm, usually by invitation only, but if you're interested I'd be more than happy to mention to the mod that you are and have her send an invitation.
I can honestly say that the writers are all marvellous. There is no random comm, no secrets, no lyrics -- and above all, no netspeak and teenie-talk allowed. The one thing that may turn you off to it is that there are also no long comment threads -- though every character there comments to everyone else, and the comments are always well-thought-out and meaningful.