I have to disagree with you on Nat King Cole. I was a part time DJ in college and I worked several shifts over Christmas so the regular staff could have some time off. Instead of our regular programming, we played wall to wall Christmas music. Over twenty years later, Nat King Cole’s version of “O Tannenbaum” (in German) is still seared into my brain. The man clearly didn’t know the German language and absolutely butchered that song. It was horrible.
It’s obviously a personal preference in the end. He has an excellent voice. His cover of “The Christmas Song” is one of the best I have heard.