Why now? I got really into movies about 5 years ago, Tarkovsky, Bergman, and Fellini are what changed my mind about the value of the medium. All have the ability to tap into and illustrate human introspection, and portray deeply flawed characters without making them champions or archetypes. There is much Dostoevsky in this kind of filmmaking.
Also, these three are rare due to their mostly apolitical approach. Many great auteurs muck up their work with outdated leftist political cliches. But some politically-motivated directors are still worth the time (Renoir, Bunuel, etc).