Mario Andretti is another I'd add to my list and if I had to choose he'd be at the top. His success and versatility across multiple forms of motor racing is unequalled: midgets, sprintcars (dirt and pavement), championship cars (dirt and pavement), NASCAR, Indy cars, F1 and LeMans. He won the Indy car championship 4 times, F1 championship, Indy 500, Daytona 500 and IROC VI. Here's a photo of young Mario at Salem Speedway, known as one of the three "Hills of Death" high banked half mile pavement speedways (Winchester and Dayton the other two). The other photo from the files is Parnelli Jones and his car owner, the legendary JC Agajanian, Jim Clark and Colin Champman at the Indy 500.