One Piece

One Piece is a very popular manga (and anime) created by Eiichiro Oda about a boy who seeks to become the greatest pirate of them all.  What I like about One Piece is the cartoony (but still very much manga-esque) art style.  The manga currently runs in the U.S. version of Shonen Jump published by Viz and the anime is available from Funimation.