Another I'd recommend is Art Spiegelman's 'Maus'.
In a slightly bizarre concept he tells the story of his father's time at Auschwitz, (Mauschwitz) with the Jewish prisoners as Mice, and the Nazis as cats. Despite it's slightly odd viewpoint (Spiegelman is definitely a rather strange chap), it's one of the few times that Comic books ever really strayed into 'Great Art' territory for me; immensely disturbing & (If I remember right) a well deserved pullitzer prize-winner.
~A