Edwardsiana is just in a class of it's own makes all other adjacent life forms seem diminutive. Lol maybe i'm embellishing, but it is the coolest plant in the world, I think. That's why I can't pick it.....
So I would have to say that Favorite Nep of all time, never owned one or seen one in real life, but that N. argentii, is a truly awesome, miniature, highly adapted plant that has some of the potentially most interesting genetic tendencies that need to be introduced into the hobby. The one that was my little kid fantasy though, was bicalcarata, I still love bicalcarata very much, but after such a long relationship, there are so many other seductive Nepenthes out there.