The arcs(storyline) keep getting better and better, man! Crocodile's plan to become King of Alabasta, Eneru's madness and now the secret of the "Missing Hundred Years"!
There are also certain scenes which touches hearts. An example, when Luffy destroyed the huge Thunderball which Eneru created to destroy Skypiea, the angels stared in awe and asked,
"Do God truly exist?" To me that scene is really awesome.
The ringing of the bell too.
Its certainly uber in terms of story and the art is pretty good, better than some...(Not gonna give examples here, i might get flamed.)