It may be true that defense wins championships, but it's quarterbacks who put their stamp on the NFL like no one else. The Mount Rushmore of the position would have to be a many-headed hydra to honor them all: preternaturally poised Joe Montana and gunslinging Brett Favre; cerebral Peyton Manning and athletic Steve Young; shaggy Joe Namath and crewcut Johnny Unitas; black-and-white pioneer Sammy Baugh and his high-def descendants, Tom Brady, Drew Brees and perhaps someday, Russell Wilson and Andrew Luck. Sports Illustrated celebrates these iconic figures and many more in a pro football...