Continuing the discussion from What is the best Bionicle set?:
In my opinion, these are the sets you should not miss buying. Though I recommend getting all if possible, if you can only get a few, these are what I think you should buy:
DO NOT get the Protectors if it means not getting the Toa. They're not worth missing, unless you're truly uninterested in the Toa but want the Protectors, the Toa should take priority on your to-buy list. I believe that Kopaka, Tahu, and Gali are the three best new Toa, in that order. The others aren't bad in any way, but are lacking compared to these three (some may disagree).
The Lord of Skull Spiders is not a bad set. However, as with the Protectors, I don't think it should take the place of a Toa in your collection, though as it is the only villain that isn't a tiny mask with legs, you may want to get this ahead of the Protectors or even certain Toa if you desperately want a villain. I think this set gets a bit more hate than it deserves, and while it is far from perfect, it is at least worth checking out.
The Protectors are pretty good small sets. I personally believe that the Earth protector is the best looking with as good playability as a protector can have, however, I know many people prefer the others. I was disappointed by the Ice protector, which I consider to be the worst out of all six, though, once again, it is not a bad set. Another thing to keep in mind is their ability to kind of combine with their respective Toa, so if you have a Toa that you really like, you may want to prioritize his or her corresponding Protector if you wish to power-up the Toa.
Overall, I think the Toa are must-buys, with the Protectors and LoSS acting more like accessories to complement the Toa. If you wish to buy all thirteen sets in bulk, that's fine too.
Let me know your opinions. I am curious about what everyone else thinks should take priority on the shopping list.