Guy walks into a bar and declares that Henry Ford was the best CEO ever, the way somebody from Baltimore might insist Johnny Unitas was the best quarterback of all time.

A woman on a bar stool calls him on it. “Hell, no! Lou Gerstner was the best pure manager to run a company!” Other patrons chime in: Bill Gates! Sam Walton! Epithets fly. Someone gets punched.

No, we don’t know any bars like that either.

But it’s an argument worth starting. So we put together a panel of business-school professors to help us come up with a list of the 20 Best American CEOs of all time. Ford came out on top. We also ranked the 20 worst, including six men who helped make today’s economy stink worse than Exit 13 on the New Jersey Turnpike.

Part of the debate is deciding what makes a great CEO—some elusive mix of results, creativity, and character. “The great ones are those who left notable innovations,” says Peter Capelli, a professor at the University of Pennsylvania’s Wharton School. Most on our list fit that description: Steve Jobs with the Mac and iPhone, Walt Disney with animation. Warren Buffett may not be much of an innovator, but he is a great philosopher—the business Buddha. We think that counts.

Doing right also counts. “Great CEOs understand their public responsibilities,” says author Richard Tedlow, a Harvard Business School professor. That’s Katharine Graham supporting Bob Woodward and Carl Bernstein’s Watergate investigation, or Lee Iacocca in the 1980s paying back Chrysler’s government bailout loans early (as if that will happen again).

Raking in money or running up the stock price doesn’t make for a great CEO. That single focus eventually collapses on itself, leading to public scorn or even legal prosecution. Certainly, it leads to a spot on our 20 Worst CEOs list, whether it’s for Jay Gould in the 1800s or Dick Fuld and his odious banking brethren today.

Don’t agree? Want to fight about it? Meet us at the bar. Also, see our 20 Best CEOs and 20 Worst CEOs lists.

Note: Condé Nast Portfolio determined these ranks ­after consulting with a panel of experts: Howard Anderson, MIT Sloan School of Management; author Steve Farber; Sydney Finkelstein, Tuck School of Business at Dartmouth College; Stewart Friedman, the University of Pennsylvania’s Wharton School; Steven Kaplan, the University of Chicago Booth School of Business; Joseph Porac, New York University’s Stern School of Business; Jeffrey Sonnenfeld, Yale School of Management; Noel Tichy, Stephen M. Ross School of Business at the University of Michigan; and Robert Wolcott, ­Kellogg School of Management at Northwestern University. Panelists were asked to consider each CEO’s record of creating or destroying value, innovation, and management skills or lack thereof.