P1 is my favorite, and I doubt I would sell him even if I stopped collecting altogether. He's my all time favorite movie creature, and I think Hot Toys did a great job with him. I just can't imagine letting him go. Definitely my most prized collectible item.
All of them. My collection is too complete to let even one go. But if worse comes to worse, I can actually name which ones I would let go FIRST. But that's not what this thread is asking.