There are tons of them. It will be hard to make a good recommendation without knowing what kind of music you want to study/play.
Here is one list, I'm sure there are quite a few others:
http://www.acousticmusic.org/Links-G...ols-sp-38.html
I think Acoustic Guitar Magazine runs a list annually too. Fur Peace Ranch (Jorma Kaukonen) is nice if you like the kind of music they offer.
Cheers,