I'm mostly into rock too, but I listened to a little bluegrass, country, and Irish music when I first began fiddle, just so I could learn the solos by listening to them... and I found a real appreciation for it.
I think the most influential stuff I ever heard was Appalachia Waltz (a collaberation of Yo Yo Ma's awesome cello talent and Mark O'Connor's fiddling, and Edgar Meyer on bass) and Appalachian Journey also by the latter. It's acoustic music at it's best IMO. That mix of classical and roots music on such good instruments played by people with so much talent is simply amazing. To this day my favorite songs to play are the ones I listened to and learned off their CD's.
I find myself wanting to learn all kinds of instruments when I hear them too... only I don't have to just hear them live. It is a terrible disorder, really, because it makes one want so many instruments that one can't afford! But oh well...
