Very few people have like Che Guevara personified the dreams of the late 20th century but the social perception of his figure is mostly split between the idealization of his figure as active revolutionary and its trivialization as mere merchandise. Néstor Kohen at La Haine, reividicates the Argentinan revolutionary leader as much more than a man of action, military leader and popular icon. The hidden face of el Che is that of a deep, well formed and visionary political thinker.
Something I did not know and that will probably surprise most readers was that, in 1965, he predicted the return of the Soviet Union to capitalism. It is his extense book Apuntes Críticos de Economía Política (Critical Notes on Political Economy).
Another advanced idea of Che was that workers needed something more than their salaries to become ethusiastic about their jobs. Similar ideas developed in Japan years later were to create what has become the paradigm of the third stage of Capitalism (toyotism, or in Marx' terms: the total subsumption of work into capital) .
Che's writings are very extensive and largely unknown (except his diaries maybe). A selection of Guevara's texts in English can be found at marxists.org and (in Spanish) at amauta.lahaine.org. His books have been mostly published by Ocean Press and can be found here at pretty reasonable prices (some works in English, others in Spanish).
Happy birthday comandante