How about these books for impact:
Sun Tzu's Art of War (Older than the 'Holy Bible' and still relevant today)
Playboy (AFAIK first porn, which revolutionised the modern world)
Plato's The Republic
Hitler's Mein Kampf (The ideology that led to the deaths of millions and the near extinction of the Jewish race) Whilst, it is a trajedy it was a major impact on world history.
Torah (it being the basis of the Old Testament)
Koran (playing a major impact in the contemporary world)
Darwin's 'On the Origin of Species'
Smith's 'The Wealth of Nations'
Marx's 'The Communist Manifesto'
The I Ching
The Iliad and The Odyssey by Homer
The Upanishads
The Way and Its Power, Lao-tzu
The Avesta
Analects, Confucius
History of the Peloponnesian War, Thucydides
Works, Hippocrates
Works, Aristotle
History, Herodotus
Elements, Euclid
The Dhammapada
Aeneid, Virgil
On the Nature of Reality, Lucretius
Allegorical Expositions of the Holy Laws, Philo of Alexandria
http://www.interleaves.org/~rteeter/grtinfluential.html