More often an anime series can count itself lucky when it can get a second or third season, that is unless you're based on a Shonen Jump power house such as Eiichiro Oda's One Piece that's produced by Toei Animation. The anime first began airing in Japan on October 20th 1999 and has produced 10 motion pictures within that time. This Saturday on May 29, 2011 One Piece hits quite the land mark of 500 episodes and going. It's reached that level with remarkably few filler episodes or arcs. Much unlike the infamous Naruto three years of straight filler episodes.
To put this number into perspective. If you add up all the Dragon Ball series of animes (DB, DBZ, DBGT) that only adds up to 470 episodes, the original Transformers is 150 episodes, and The Simpsons reached 480 episodes only recently. One Piece still hasn't even hit the time skip and to Fish-Man Island, the literal half-way mark of the Grand Line. Currently, the series is within the middle of the Dawn Island arc, the flashback part of the story where Luffy is remembering how he and Ace first met. If they don't add any fillers after this, it's the final arc before the two year time skip. One Piece could look to go on to be one of the longest anime series ever.