A Charlie Brown Christmas - Vince Guaraldi Trio
The Christmas Song - Nat King Cole
Christmas Eve and Other Stories - Trans-Siberian Orchestra
Joy to the World - Mormon Tabernacle Choir
a two-disc set called The Night Before Christmas which has classics like "White Christmas" by Bing Crosby, "Rockin' Around the Christmas Tree" by Brenda Lee, "Feliz Navidad" by Jose Feliciano and Mel Tormé's version of "The Christmas Song"
I also own the two Christmas releases by Diana Krall, one by Holly Cole. I recently got Martina McBride's Christmas album, Smashed for the Holidays by Jacqui Naylor, the Acoustic Christmas release that has a number of the artists from Steve Vai's Favored Nations label and Merry Axemas, which is another Steve Vai involved project.
As far as specific songs there's
"Santa Claus is Coming to Town" by the Pointer Sisters
Run-D.M.C.'s "Christmas In Hollis"
"All I Want for Christmas Is You" by Mariah Carey
"Santa Baby (Gimme Gimme Gimme)" by Willa Ford
"Rock You Hard This Christmas" by The Dan Band
Now I like the usual Christmas songs but I also enjoy the apathetic ones
Everclear's "i will be hating you for christmas"
Ramones' "Merry Christmas (I Don't Want To Fight Anymore)"
The Kinks' "Father Christmas"
John Lennon's "Happy Xmas (War Is Over)"