Jimi Hendrix's cover of Bob Dylan's "All Along The Watchtower" is arguably the greatest rock song ever.
Ther are several. the top 3 I can think of from the top of my head, although one was already mentioned in a previous answer: "All Along the Watchtower" written and originally recorded by Bob Dylan. Jimi Hendrix did a much better version. "God gave Rock and Roll to You." Orginally recorded by Petra. I think it was KISS who did a much better version. And "Blinded by the Light" Written and originally recorded by Bruce Springston. Manfred Mann's more famous version is much better.
Johnny Cash: "Hurt"
Soft Cell: "Tainted Love"
Manfred Mann’s Earth Band: "Blinded by the Light"
Chester See on youtube does a lot of covers that are much better than the orignal Top40 songs. For instance, his Katy Perry cover of The One That Got Away and Taylor Swift's "We are never ever getting back together" are amazing.
whoever did the song "Red Red Wine , I was just singing it and saw this question . I see now it was UB40
There are a few I can think of, but not many.
I like CCR's version of "Proud Mary" better than Ike and Tina Turner's.
I like the Talking Heads' version of "Take Me to the River" better than the original. (I forget who did it.)
I like Gary Jules' version of "Mad World" (from the movie "Donnie Darko") better than the Tears for Fears original, although that one was already good.
I like Joan Jett's version of "Crimson and Clover" a little better than the original version by Tommy James and Shondells.
Yes, but now that you ask the question, I can't bring myself to remember.
Oh, wait. Here is one: Breathless, by Jerry Lee Lewis, but the version recorded by X. It is thoroughly spectacular.
snowblind - system of a down (black sabbath cover)
somebody that I used to know - walk off the earth (gotye cover)
... and this. https://www.youtube.com/watch?v=NsZFxPDxKaQ
That Power of Love cover thats on the radio atm
pet shop boys - always on my mind.. sorry willy
and a few more. not many