I like photos that tell a story and convey a strong emotion.  The images don't necessary need to be "pretty" or "happy."  I  admire the work of spot news photographers and of Ansel Adams.  I like looking at Pulitzer Prize winning photos, even if they are of unpleasant or disturbing images.  To me, photos should tell a story and make people think in a new way.  Photos should illicit a strong reaction.
 A powerful photograph can change the world and the way we think.