This is almost impossible to answer. Philosophy covers such a massive area, one cannot really just pick a greatest. There are too many different topics to cover.

Thus, I am inclined to say Aristotle, simply because the guy had something to say on pretty much every and any matter. That's not to say that he was the best at every subject, but he was probably the most well rounded philosopher the world has ever seen.

It's very interpretative. It comes mostly down to what you're looking for in life.

I can see Liber liking Descartes since that was about how we can't really know much except that we exist since we're thinking... you know, considering the experimentation Liber does with the dergs.

I take dergs myself, and I like Descartes. I suppose my favorite would be Socrates because he was all about questioning every answer you'd try to give. He never just accepted what he was told, he'd say "yes, but what if..." and then people would realize how their perceptions of common things like justice and truth were nowhere near complete. they were based more on axioms that failed to deliver. Considering how much I hate axiomatic principles, I can relate to Socrates.

I also like Nietzsche a lot yet I don't read as much of his stuff. I like his anti-collectivist views quite a lot. And even though he seemed to be afraid of the Herd adapting Nihilism, I, myself, am pretty Nihilist in a lot of ways.

So those are my two favorites.

Very difficult question to answer, but for me it falls mainly on Plato. I LOVED reading "The Republic" and especially loved "The Symposium" and "Critias". I recently wrote a speech/ debate on "The Myth of Atlantis" and Plato's "Critias" was my first port of call and I have to admit I've read it more times than I can say- it's just a bummer that he never actually finished it cause it stops at the good part!

I don't recall his name, but it was probably that guy who worked for Nabisco company and came up with the idea of spray cheese in a can. I mean you put it on a cracker, a chip. Just squirt it in your mouth. It's pure brilliance.

I think Descartes was the greatest philosopher - "I think, therefore, I am."