There has been much talk of whom President-elect Barack Obama will name as his Treasury secretary. The guessing game on Wall Street and in Washington, serious stuff even before the election, has become even more intense. A job that was once a good part ceremonial - with the ultimate perk being your signature on the nation's currency - has become full-time serious. The new Treasury secretary is probably Obama's most significant appointment, and arguably the first significant decision the next president will make.