I have posted this first link before, but I watch and listen to it every Christmas. It has been covered by many other artists, but my favorite cover is #2 below. Imagine, (paronomasia intended and #3 below), what wonderful music it would have been if John Lennon and Sarah McLachlan had been able to perform Happy Xmas (War is Over) together. This song never fails to make me think and exercise the tear ducts.
Wishing you all a wonderful Christmas!