I allways think I'll need the speed/agility type pots for something and never do. I've got a house full of crap in RL I'll never use either.
Exactly my situation. For the whole first act and half of the second, I though that if I meet a trully bad-donkey character, I'll have to use up all my potions: It's a Baldur's Gate 2 reflex. But I killed one, two, three different entities and never I had to use the potions.
By the way, Kult won't have healing potions, which I think is a boon and forces player to be more careful.