Pink Floyd is soooo great to just sit down, close your eyes, and chill to.
As for me,
Metallica - Nothing Else Matters - Excellent, but very depressing song for me. There is really no specific even that ties my life to this song, but whenever I hear it nowadays, I have to turn it off, becuase it depresses me so much.

Crazy Town - Butterfly - Fond memories from when I first met my girlfriend.
Lifehouse - Hanging By a Moment - More fond memories from when my girlfriend and I first met.
Can't really think of any other songs besides those that stick to any specific events that have happened in my life.