Best delivery? Lincecum. It's unorthodox but from what I've read, it's meant to put less torque and less wear on the shoulder.
As for a personal favorite, it has to be Hideo Nomo, just for the novelty of the tornado windup and the nostalgic fondness of a spectacular rookie year. Another I thought was cool was from Ben Weber, Angels reliever back in the early 2000's (also played a part in the '02 World Series title). He used to make this priceless cringing face, high leg kick, with what it appeared to be a double-clutch reluctance to hurl it before unleashing such a wild delivery.
His follow through is a bit more restrained than what it was from college, but basically the same elements are there. It seems like that upper half of his body twists and builds up the momentum of the pitch while he has the ball down more than the average pitcher would to get the most out of the motion.