Q: Can be from any type of racing - Nascar, F1, Indy - whatever - I personally think it would be Mario Andretti - he won at Indy, won the Daytona 500, and won a F1 championship too.
A: Gotta go with Mario. Indy, Daytona, World Driving Championship, Championshio of Makes (LeMans types), USAC Dirt track, IRL. He's done it all, and the only other drivers that even come close to his expertise and versatility might be Graham Hill or Jim Clark.