Jean Baudrillard
Jean Baudrillard died yesterday. It'd take more than just a few sentences to even come close to summing up the complexity of his writing, but needless to say his work had a massive influence on me and his thinking figured heavily in both my undergraduate thesis (which was about Baudrillard, Debord, and the Situationist International) and my graduate dissertation (which was about Baudrillard, Derrida, Lyotard, and economics).