[Kanji_The_Wanderer]

Seijuro Hiko (Samurai X, Trust): "The moon peers down on a diseased world... There is no cure for the disease, an entire race walks mindlessly into destruction. Not even a man of colossal power, would be able to prevent the inevitable."

Not sure if it's my all time favorite anime quote, but it is the first that came to my mind, so it's pretty high up there.