I like several of the ones mentioned above, but two of them oddly enough stand out for me.
Dickens' Dublin - I sometimes get a tug on the heartstrings thinking of the little boy/girl who "tells the story"
Snow - this song amazed me. One incident I had involving this: I was working at a job, close to the implementation of new software. The software was NOT recommended by me, and I and one other actually wanted to drop it. Political pressure kept it going. So there I was, doing 14-15 hour days for two straight weeks, doing something I couldn't believe in. I was stressed in a HUGE way, and it was affecting me emotionally and physically.
I came home one night, put on the mini-CD that Snow is on, and shut out the lights. Whe that song ame on, it hit me so hard, I literally had tears rolling down my face. I couldn't stop. Very catharctic moment, and therefore one of my favorite songs.
Sorry for the babbling. I agree she is one of the best!