* The original song: The song "Rudolph the Red-Nosed Reindeer" was first written by Robert L. May in 1939. It was originally a promotional jingle for Montgomery Ward department stores. This version is considered the original and is often referred to as the "classic" version.
* The popular version: The version most people know and love is the one performed by Gene Autry in 1949. This version became incredibly popular and is often considered the definitive version of the song.
* Other versions: Over the years, countless artists have recorded their own versions of the song, from Bing Crosby to The Chipmunks to even Weird Al Yankovic!
So, it really depends on what you're looking for. The original song by Robert May is historically accurate, while Gene Autry's version is the one most people associate with the holiday.
You can easily find both versions online to hear the differences for yourself!