I would go for either Itachi or Jiraiya. Itachi for being the most ninja like as SilentSnake says and making the ultimate sacrifice of not just dying for his belief but living for it too. Jiraiya because he was probably the most influential after the Hashirama and Madara. He taught two Hokage, was given the job of being Godaime but turned it down (Tsunade was never an equal to him or Oro) and brought Senjutsu in to he ninja scene without which the Jyuubi/Jyuubi Jinchuriki couldn't be defeated.

Worst, probably Sakura for the crap the others had to endure because of her. And her silly contributions to fights which anyone could have done.