I just visited James Madison's house Montpelier yesterday. He may not be the greatest, but he is underrated. He is called the "Father of the Constitution" and his note taking is the reason why there are any records of what happened that summer in Philly with the writing of it.
His research skills were unmatched reading thousands of books to find the best form of government for us.
The British invaded us in the War of 1812, and it was the last time foriegn troops were on our soil.
He also saw over the completion of the Louisiana Purchase.
President John Adams said Madison did more, and the country grew more in his 2 terms than his 3 predecessors (Washington, Adams, Jefferson).