There's a little useful stuff on AT, but the signal-to-noise ratio isn't good. Archery-forum.com, the Aussie forum, is better.
AIUK is a fun and interesting forum to be involved in. However, at the risk of being pelted with cake I have to say my favourite is still the Sagittarius board, although it hasn't been quite as good as late. Then again, its been around for a while and has always had its ups and downs.
Each board has something different to offer so I think it's a good idea to at least read others, if not always participate.