This one's just beautiful, with some of the best lyrics of any song I've heard.
The more I know, the less I understand/All the things I thought I knew, I'm learning again/I've been tryin' to get down to the heart of the matter/But my will gets weak/And my thoughts seem to scatter/But I think it's about forgiveness.
The message of letting go and moving on is one that I could stand to remind myself of every now and then. Plus, his voice is one of my favorites in rock. Here's a live clip (from the Hell Freezes Over reunion concert, I believe) of Don Henley's "Heart of the Matter."