Have you heard the Casting Crowns "I Heard the Bells" - my all-time favorite!
http://www.youtube.com/watch?v=M7670CXvPX0 (that's the live version, I like the recorded even better)
Also, if you like instrumental, check out
The Piano Guys.
And something else a little different
The Priests.
I also LOVE Rascall Flatts "God Rest Ye Merry Gentlemen."