I've collected a bunch of Christmas music. We like:
Neil Diamond, A cherry cherry Christmas
Celtic Women, A Christmas celebration
John Denver and the Muppets
Mannheim Steamroller
Sheryl Crow, Home for Christmas
Jethro Tull, The Christmas Album (which is fantastic in my opinion, kids love to dance to it)
Sleigh full of Songs (collection)
The Nutcracker
Josh Groban, Noel
Michael Buble, It's beginning to look a lot like Christmas
John Zorn, A Dreamer's Christmas (which I really like, though is "dreamy")
Willie Nelson, The Classic Christmas album
John Denver, The Classic Christmas album
The Chieftans, The Bells of Dublin (another great one, kids love to "Irish dance" to it)
Johnny Cash, Country Christmas
And of course the classics, Burl Ives, Dean Martin, etc.
This year, I bought some more (Chris Isaak, Ella, Pentatonix, Idina Menzel, Johnny Mathis, A Christmas Gift for You), but haven't had time to listen to them enough.