Favorite: John Locke. I can relate to the way he thinks, which makes him a joy to read even when I disagree.

Least Favorite: Nietzsche. I may be on the path to nihilism myself, but that doesn't mean I thank Nietzsche for it. I mean, seriously, could anything be more depressing?

-- to answer my own question, I suppose Nietzsche + Darwin is even worse.

SigmaX