Left: 1908 Ford Model T with a 20 horsepower engine and a top speed of 45 mph. Source: centennial.ucdavis.edu Right: 2014 Ford Mustang Shelby GT500 with a 662 horsepower engine and a top speed of 189 mph. Source: motortrend.com
Ford "Businesses that grow by development and improvement do not die."
Automobiles -Henry Ford 1929 (thehenryford.org Henry Ford Quotations)
The biggest legacy Henry Ford left behind is definitely the Ford Motors Company. Who would've thought that a small start up in Detroit would expand in just a century to a 64 billion dollar company(45th in the world) employing well over 150,000 people in nearly every corner of the globe.
"We have had just one main purpose during these years, and that is to give the people transportation of the most dependable quality at the lowest possible cost. Our car was called the "Universal Car" thirty years ago, because it fulfilled so many needs; it is "The Universal Car" today for the same reason." -Henry Ford 1938 (thehenryford.org) Henry Ford Quotations.
On 2012 Ford Motors reached an unprecedented amount of 350,000,000 cars made in factories from the workshops of Dearborn to the jungles of Thailand. With that, Henry Ford's name will truly be remembered in every one of those cars from his assembly line method in making the cars to his high wages in motivating the workers. There is really no one else that has left this big of a legacy on the world in the 20th century.
"A manufacturer is not through with his customer when a sale is completed. He has then only started with his customer. In the case of an automobile the sale of the machine is only something in the nature of an introduction. If the machine does not give service, then it is better for the manufacturer if he never had the introduction, for he will have the worst of all advertisements-a dissatisfied customer." -Henry Ford (My Life and Work p.41)