My childhood Decemebers were filled with version’s of this song. Over and over.  Also, Wikipedia informs me that this was former President Richard Nixon’s favorite yuletide tune.  So, game over.  

I had a very tough time picking a ideal version, because there are a lot, and none clearly stand out. What I really love is a unique arrangment (without vocals) from Harry S Meane, though I can’t seem to find a trace of it anywhere.  Thus, here is the original, first released in the middle of the century.  

The Little Drummer Boy – Harry Simone