And hey, for anybody who's theory-averse or has suffered "theory trauma"

, a perfectly useable system for basic harmonic analysis is to classify the harmonies as simply "tonic", "dominant" and "other". You don't really have be able to identify a half diminished or secondary dominant chord to get a lot of value out of studying harmony. For people with normal musical aptitude I think it's a big deal just to be able to always hear where the
tonic is while you're playing.
But I think to really know harmony and theory relating to guitar you've got to first know your basic scales and arpeggios and be able to sing them as you play them. Take an ear training/musicianship class at your local college and it's a lot of singing... that's because if you can sing the pitch relationships, you know they're in the head. And if the sound
isn't in the head, terminology is just a bunch of words with no real meaning.
Tim