One Piece remains the only over-popular anime that I continue to watch. Although there are often gaping plotholes, they still occasionally use original attacks rather than a stronger sword (bleach) or a bigger explosion (naruto). They even occasionally explain why an attack has become stronger, and it doesnt just involve more spirit, more chakra, more eyehax. Plus, where the fuck else are you going to find r34 of cyborgs, mermaids, fishmen, skeletons, bestiality, and stretchydick all in one place?
A Fairy Tail is fine too.