The obvious masterpieces are Another brick in the wall and Wish you were here.

But let's say you don't like those two. Another great whole-life-story-of-a-person song is Time. It sums up a majority of people's lives. You go through your life trying to figure out what you need/want to do in life...and then it's over, you never figured it out. Great introspection song. Makes you ask yourself...