There are three kinds of people in the world: leaders, followers, and people who just want to be left alone.

Comments?

(i.e. "There are two kinds of people in the world: those who comment on blogs, and those who don't."

"There are five kinds of people in the world: four kinds who believe there are five kinds of people, and one kind who doesn't."

"There is only one kind of person in the world--me--because there cannot be a multiplicity of people." --Zeno of Elea [he didn't really say this, but easily could have])