Great thinkers? Have you ever read Leviathan? Hobbes is far too rigid in the framing of his arguments. That's not to say he wasn't a great thinker, but I can't help but wonder whether he actually read his own work after he completed it.
Also, while these philosophers were certainly the forerunners of the "atheist awakening" we're experiencing today, I wouldn't play down the contribution of modern activists and thinkers.