Bismarck. Because he is controversial.

Being german my first exposure to Bismarck was "He's the father of our Nation. His schemes allowed the geman states to become one" which is true. But later we learned how he created out-groups as a tool to unite people. Groups like "jews" or "catholics", and probably many others I don't recall.

He is not my favourite because he is such a golden boy, but because he is the complete opposite. And because the way he was discussed in history class throughout the years: It was a wonderful decunstruction of his myth.