Inspired by @Laflamablanca91, here are my favorite covers of all time. Note that these aren't necessarily a list of where I think the cover is better than the original (example, I actually prefer the Cale versions of Cocaine and After Midnight to Clapton's).
  1. Hard to Handle - Black Crowes
    Otis Redding
  2. When the Levee Breaks - Led Zeppelin
    Kansas Joe McCoy and Memphis Minnie
  3. Not Fade Away - Grateful Dead
    Buddy Holly
  4. Cocaine - Eric Clapton
    J.J. Cale
  5. After Midnight - Eric Clapton
    J.J. Cale
  6. All Along the Watchtower - Jimi Hendrix
    Bob Dylan
  7. All Along the Watchtower - John Mayer (@john) (Live at Made in America)
    Bob Dylan
  8. Superstition - Stevie Ray Vaughan
    Stevie Wonder
  9. Catfish Blues - Gary Clark Jr.
    Robert Petway
  10. Tumbling Dice - Keith Urban (Live on Late Night with Jimmy Fallon)
    The Rolling Stones