I haven't read Nietzsche in a while, but I used to quite like him; he had a lively prose style, at the opposite literary pole from writers like Kant or Marx, and was a brilliant epigrammatist. And he was one of the pioneers of some ideas that became important to twentieth-century thought—in particular he was one of the first thoroughgoing cultural relativists. (Note that I'm not a cultural relativist; but I think the clear and consistent statement of that position was important even if, as I believe, it turned out to be wrong.)