I'm not going to go through all of the posts, but...
Donnie Hathaway - This Christmas:
http://www.youtube.com/watch?v=pj1mVUEHeUE
Christina Aguilera - Oh Holy Night:
http://www.youtube.com/watch?v=G4J40bG2TYo
Mariah - All I Want For Christmas Is You:
http://www.youtube.com/watch?v=yXQViqx6GMY