Mata and Bohrok. Story significance, easy storage, displays kanohi/ displays hanging set. Basically they were unquestionably the best. Oh, and metallic lids! Least favorite, probably the barraki, they look awesome but... Tough to stack, no collectables display, and you can't fit the sets in them without tearing the set in half :(I would say the piraka, cos the spine geta all twisted, but that's not really the cans folt.