An individual song needs to be amazing for it to stir my emotions. Often times, my musical attention span is greater than the length of a single song. This is one of the reasons I like classical pieces or scores, because it will often take a whole album to put me through a whole emotional gamut. Some of the more notables...
Transformers (2007) original score
This Binary Universe, B.T.
300 original score
Unleashed soundtrack, by Massive Attack
Final Fantasy VII: Advent Children original soundtrack
Gabriel Faure's Requiem
William Shatner's Has Been
... Interesting that William Shatner can be right up there with Faure, but it's true -- Shatner's album honestly makes me hit every emotion. There's actually a "song" (a poem, actually) track that I need to skip whenever I listen to it that makes me instantly cry every time.
As for songs, there are several that I know I can turn to when I want to feel a surge of emotion.
The theme from HBO's John Adams
OneRepublic's "Apologize"
Snow Patrol's "Chasing Cars"
"In a House, in a Heartbeat" from the 28 Days Later soundtrack
Killswitch Engage's "My Last Serenade"
Coldplay, "Yellow"
Any of Chopin's nocturnes
There are tons of other pieces out there that drive me to choke up, to feel triumph, or to feel like I'm soaring, but to list them all would be to bore everybody else!
