I have felt, since first I heard it, that The Fireside Largo from Vivaldi's Four Seasons is the most emotive piece of music ever written. It stirs the Soul.

After that, I would agree with others on So Lonesome I could Cry, Long,Long Trail, and Shenandoah. To those I would also add McCartney's Yesterday, Gram Parson's Hickory Wind, and Corral Nocturne from Copland's Rodeo.