Nothing is quite like TB but some places I go:
I subscribe to a Vinyl discussion via email called Phonogram. They are even bigger dorks than TB's but have really interesting conversations about pressings, history, and the like.
To subscribe to Phonogram, send email to majordomo@phonogram.net with the command "subscribe phonogram" in the body of the message. To subscribe to Phonogram Digest, send email to the same address with the command "subscribe phonogram-digest." If you want to subscribe an address other than the account the email is coming from, append that address to the subscription request (e.g. "subscribe phonogram my-other-address").
Audio Asylum is interesting.
http://www.audioasylum.com/index.html
I lurk the vinyl asylum and the tube asylum and the high efficiency speaker forums. I stay out of the mix there as it can get a little petty and I don't have time for those kinds of interactions.
Audiogon is really interesting too. I've done well with the equipment trading pages there.
http://www.audiogon.com/index.html