Heard On the Turning Away (Pink Floyd) on the radio on the way home from work.
It's one of my favorites, but it's so moving (always brings tears to my eyes) that I can't listen to it very often.
There were two versions on YouTube, the one I'm embedding here and another one that was paired with a Carl Sagan clip and some computer generated celestial images. I liked the latter, but found it to be a bit manipulative, so I'll include the former, live version (which has a great section with the whole audience singing along) which suits my purposes just fine:
Note: There is an extensive instrumental section at the end.
The lyrics, if you would like to see them, are located here.