Lt. Felix Gaeta - How was he able to move about during the Cylon occupation of New Caprica freely and gather all that intel? Plus what happened that made him want to kill Baltar? These questions will have to be answered soon, the big reveal about him could just be that he is gay or something else unrelated. I dunno he seems just enough under the radar yet always around and sometimes shady.
President Laura Roslin - the half cylon baby helped stop her cancer, although it did come back, it did strike me as odd. Also she is prone to visions and is very religious.