Silent Night and Greensleeves by Mannheim Steamroller both bring me to tears.
The challenge is not to wear out the charm by listening to them too often. I only listen to carols in December. It’s tough to avoid be overexposed to carols when you are out and about, but I manage somehow.
One of my favorites (especially since having babies of my own) is called Mary’s Lullabye written by Wanda West Palmer, it’s not mainstream in the least, so the only “good” recording I could find was not offical and just has pictures someone posted with the music. The singer is not listed on the album, but the orchestra is the London Philharmonic Orchestra and it was recorded in 1995 http://www.youtube.com/watch?feature=player_embedded&v=GEr4HaxaQuQ