Eric Whitacre is a decent composer who is a little bit too popular right now for his own good and who sometimes is a bit too experimental for my tastes.
2 Samuel 18:33 is one of the most poignant passages in the Bible.
Eric Whitacre temporarily transcended time, space, and truth, saw human emotion through God's eyes, assumed superhuman powers, and rendered 2 Samuel 18:33 into 15 minutes and 5 seconds worth of crystallized grief in musical form that he named "When David Heard."
"When David heard that Absalom was slain, he went up into his chamber over the gate, and wept; and as he wept, thus he said: 'my son, my son, O Absalom my son... would to God that I had died for thee; O Absalom, my son, my son!...'"
Alright, so that was a bit theatrical. BUT - it is, in my opinion, simply one of the most heartrendingly beautiful songs in existence. Right now (and for the last year or so), it's my favorite song in existence.
Another one which unexpectedly moved me in an profound way was the disc "Cathedral Classics" by the Dale Warland Singers, which includes Samuel Barber's "Agnus Dei" (a cappella version of "Adagio for Strings"), Frank Martin's "Mass," Howell's "Requiem," and Allegri's "Miserere mei, Deus."
I love music, especially sad music, and I've been fairly emotionally involved in listening to some songs. But that was nothing compared to that song and that disc. Both of those hit me significantly harder than any music before or since.
Unfortunately, the Dale Warland disc has been overplayed. I know each piece so ridiculously well that the same magic isn't there anymore. They're still fantastic, gorgeous, perfectly performed gems of the choral world, but nothing hits you like the first few listens...