reading through the thread i didn't see my favorite so here it is...
Jon Anderson (lead singer for YES back in the day)... it was his "Three Ships" Christmas album. The whole things is IMO one of the best RR Holiday albums.
Here is his rendition of "Oh Holy Night":
Here is "Three Ships" a classic:
My other favorite is Cannon Rock by Trans Siberian Orchestra:
and an amazing all instrumental version of the same "Cannon Rock" in D:
Cheers,
Thom
PS: I ran 8 record shops (yes we had vinyl & 8 tracks!) back in the 1970's and 80's. Fun stuff