I had a hard time deciding between One Piece and Bleach (never cared for Naruto), but in the end I voted Bleach. I think One Piece has the advantage of having a story that can avoid really naming anything filler, because it can all tie into the main storyline, so nothing feels like it's dragging on. And in this regard, Bleach is the worst. Seriously, FILLER WITHIN FILLER. WTF?!?!?
(It's at that point that I stopped watching Bleach.)
But I still voted Bleach because I thought it had the most enjoyable aesthetic, and I liked the characters, setting, and canon storyline the most of the three. And some of its filler was tolerable, namely the Bount arc and Muramasa arc, before it actually produced FILLER WITHIN FILLER!!! /fanrage
When Bleach stays in canon, it's far and away the best of the three to me. The problem is, of course, the same problem that does plague the other two as well and necessitates the need for filler: that the anime catches up with the manga too quickly. If the producers of the anime didn't feel they need a new episode absolutely every freaking week, they could simply refuse to make filler altogether and stick to canon, producing it in seasons much like Western shows based on books do. Or, they could, you know, wait until the manga is finished to produce the show in the first place, thereby saving both the anime producers and the mangaka much of these types of headaches to begin with.
