Who are the greatest head coaches in the history of the NFL? Do current top coaches such as Sean Payton, Mike McCarthy and Mike Tomlin belong in the same conversation as legends like Bill Walsh, Vince Lombardi and Don Shula? This was the question put to a blue-ribbon panel of ESPN's NFL experts and the results of their Top 20 vote will be unveiled on ESPN.com one by one each day starting on Thursday, May 23. Who will make your Top 20? Make your picks below and see how they compare to SportsNation.
Editor's note: Jimmy Conzelman's first championship came in 1928 when the team with the best regular-season record was awarded the championship.