Great advice!

I too am a chord progression guy, though I play melody notes fingerstyle. In fact, I learned so much based on the chord structure tha I have trouble memorizing a fiddle tune if I DON"T know where a note lies in the chord.

I have found that I, like JP, use the Low E string to determine the key from a cd but I do so because I'm generally trying to figure out what the GUITAR player is playing and, barring some alternate tuning (even DropD) I can detect the fingering the guitarist is using (even with a capo), because the lowest note is close-ended.