It doesn’t happen often, but occasionally a cover will actually turn out better than the original version. Below are a couple that definitely fall into this category for me (though I do like the originals as well).
BALL OF CONFUSION
The Temptations (original version)
Arch Enemy (cover)
Judas Priest (original version)
WHERE DID YOU SLEEP LAST NIGHT
Leadbelly (original version)
Any covers that you feel are better than the original?