[wagglebee]

I would go with Leonardo, John Stuart Mill (who I disagree with on most things), Newton, Thomas Paine, Thomas Jefferson and Benjamin Franklin.

[Siena Dreaming]

Personally, I think one of the Founding Fathers with the biggest brain was John Adams.

[Leo Carpathian]

You are forgetting to put Nikola Tesla as a #1 man who gave us most! All others pale in comparison and magnitude of their contribution to mankind. The greatest engineering genius and brain!

[quantim]

Newton remains as the unbridled genius who was able to contemplate the Universe and convert that thought into mathematical formulas that launched a technological revolution that remains today.  Of course many would argue 'Einstein' but he had quite a body of work before him, Newton did not.

Jefferson I suppose remains as the greatest political genius, at least as far as our country is concerned.  Fortunately his ideas and methodology worked and we are here to brag about him.

da Vinci concentrated on more Earthly things, and remains as the greatest 'artist' of that century. 

There are arrays of men and women on orders of magnitudes of smart people through out history with amazing historical perspective but there are very few actual 'geniuses.' 

There are some that think Michael Moore is a genius.

There are some that think John Kerry is brave.

But there are certain things in history that are absolute and cannot be rewritten.