My favorite Christmas song ever, sacred or secular, is John Lennon's "Happy Xmas (War is Over). Below is a YouTube video featuring the song, but be warned: it's some depressing shit.
It's like one of those ads for Christian Children's Fund, what with the famine and war and death and whatnot. Very Christmasy. I post it because of the lovely song, and because it can't hurt to think for a few minutes about those less fortunate than us, who will be having a hard time of it while we make merry over the holidays.
Merry Christmas to all, especially those who don't know what one feels like.