Which president's middle initial "S" famously stood for nothing?

Which president was nicknamed "The Great Communicator"? Which president was nicknamed "Dubya"? Which president is called the "Father of His Country"? Which president was known as "The Great Emancipator"? What was Ulysses S. Grant's original first name? What was Bill Clinton's birth name? What was Gerald Ford's birth name? Which president was a famous Rhodes Scholar at Oxford?