Euclid The Elements
Arrian The Campaigns of Alexander
Garmonsway (trans.) The Anglo-Saxon Chronicle
Komroff (ed.) The Travels of Marco Polo
Haydn The Counter-Renaissance
Braudel The Mediterranean and the Mediterranean World in the Age of Phillip II, Vol I&II
Pascal The Thoughts
Spinoza The Ethics
Christianson In the Presence of the Creator: Isaac Newton & his Times
Newton Opticks
Newton Principia (get the modern English translation by U.C. Press)
Hampson The Enlightenment
Voltaire Candide
Rousseau The Social Contract
Boswell Life of Johnson
Goethe Faust
Phillips The Cousins' Wars
Schom Napoleon Bonaparte
Heidler & Heidler Old Hickory's War
Babbage On the Economy of Machinery and Manufactures
de Toqueville Democracy in America
Darwin On the Origen of Species
Foote The Civil War: A Narrative
Maurois Disraeli
Twain Life on the Mississippi
Spector Admiral of the New Empire, The Life and Career of George Dewey
Cardwell The Norton History of Technology
Abbott Flatland, A Romance of Many Dimensions
Meyer & Brysac Tournament of Shaddows, The Great Game and the Race for Empire in Central Asia
Doughty Travels in Arabia Deserta
Lefevre The Golden Flood
Massie Dreadnought, Britain, Germany, and the Coming of the Great War
Lawrence Seven Pillars of Wisdom
Durant The Story of Philosophy
Cardozo The Nature of the Judicial Process
Schapiro The Communist Party of the Soviet Union
Popper The Logic of Scientific Discovery
Kershaw Hitler: 1889-1936 Hubris
Blemenson (ed.) The Patton Papers (1940-1945)
Hayek The Road to Serfdom
von Mises Human Action
Skinner Walden Two
Chambers Witness
Kuhn The Structure of Scientific Revolutions
Guevara Guerrilla Warfare
Cleaver Soul on Ice
Lacey The Kingdom, Arabia & the House of Saud
Durant The Lessons of History
Hackworth Lessons Learned, Vietnam Primer
Quigley Tragedy & Hope: A History of the World in Our Time
EDIT: Just remembered two more
Hobbes Leviathan
Locke Two Treatises of Government
(Since you've read Faust and the intial post mentions Gibbon's Rise and Fall, you might be interested in Theodor Mommsen's "History of Rome" as well.)
P.S. I'm heartened to see Mises and Hayek on your list. I recommend adding Burke and (especially) Carlyle. If you can fully digest Carlyle, your fear for democracy and republican government will turn to panic, and your journey to the Dark Side will be complete.
Tuchman A Distant Mirror