The annoying, but correct answer, is "The one the performer puts the work into perfecting".
I get a huge amount of mileage out of just jazzing with controls and palms. I'll open a card set with a line like, "I'm going to share a secret with you. When I hold a deck of cards in my hands, you don't know what's happening. I'll make sure it looks like you know, but you don't." Then I just make it up as I go - card to pocket, card under glass, CAAN, irreversible card, ACR, etc. That's how I secured a presentation at a major university.
The trick I personally think is most powerful is one I haven't performed for many people yet. I call it A Psychic Game - a mixture of Out of My Mind and Reds and Blacks.