You are missing Socrates, the smartest human who ever lived, and the biggest impact (through his heirs) on the world, if that's what you mean by "effective".
I felt everyone would pick Socrates. A lot of people only know Socrates, Aristotle, And Plato. I just want to know who people would pick out of the choices. I'm not saying they are the best just want to know who people would choose out of the choices.
OK, then Plato, Socrates' student, by proxy. Bacon was a philosopher who revolutionized the world by coming up with modern science. DesCartes was a philosopher who also revolutionized the world, but in mathematics, while his flawed philosophy did untold harm. Nietzsche, and the Scotsman, John MacMurray were two of the most powerful, in my view, but one is famous, one is not. Aristotle, Plato's student, and the teacher of Alexander the Great, had an enormous impact and was a philosopher. Marx and Confucius had enormous impacts as well, but weren't, strictly speaking, philosophers. Like the great philosopher, Jesus, neither Socrates, nor Confucius ever wrote anything down, though all three can claim to be founders of civilizations. Socrates was the earliest, and when he was put to death by his own people (like Jesus) at the age of 70-something (Jesus was in his 30s--a shame), Aristotle was just a little boy, and it would be more than three centuries before the three wise men would follow the star to Bethlehem. Dostoevsky, who took Jesus seriously, was probably the greatest novelist to ever live. He wasn't a philosopher, but went philosophically deep in his novels, as did Kafka. Locke probably had the biggest direct impact on us Americans. There, that's my two cents.