Kelso
Five-Time Horse of the Year (1960-1964)
Earnings: $1,977,896 ($12 million in 2002 dollars)

Though he had a notorious temper, Kelso's achievements year after year earned him greatness -- and a devoted fan club. The three-year-old gelding, great-grandson of Man o' War, raced through eight seasons and claimed more top honors than any other horse before or since.