Oh, man - I LOVE Christmas music! It's so hard for me to choose a favorite song, so here are a few of my favorite albums:
Carpenter's Christmas Portrait album
Time-Life Music: Treasury of Christmas - Holiday Memories
*Michael W. Smith - Christmas, Christmastime & It's a Wonderful Christmas (I have all three albums, and there's only one song I don't like.)
*Steven Curtis Chapman - The Music of Christmas & All I Really Want for Christmas
Manheim Steamroller - Christmas Celebration
* These are Christian singers, and the majority of the songs they sing are original, and not secular.