All I'll say is that this one perfectly puts together the drama side of Angel Beats. I think I've already watched it more than a dozen times since I found it a little while ago... it's just that good. One can only imagine what this show would have been like if the executives had actually let the originally planned 26-episode version air.
Anime: Angel Beats!
Song: Iridescent (Linkin Park)
And since I can't think of an AMV that'd compliment this one... the anime version of My Song.