"Hallelujah" by Jeff Buckley
By the way he lets out that breath at the beginning, you know it's gonna be a great song. Seriously though, and this is a well known fact, this is one of the greatest covers ever and one of the most beautiful songs ever period. The greatness of this song has much to do with its lyrics; "Hallelujah" is one of the finest written pieces of music/poems I've ever had the pleasure of digesting. But no one does it better than Buckley--although John Cale does a mean version, too. His voice is so vulnerable, his guitar glimmering with despair. He delivers the message so pristinely, so emotionally (but not overly emotionally). I must admit: I almost cry every single time I listen to it. I almost cry when I think about it. I'm almost crying right now.