Everyone knew who was going to be in the No. 1 spot. Anderson Silva has two of the greatest KO's in UFC history.
First, after catching a James Irvin mid-kick, Silva punched his defenseless opponent once in the face. That was all it took. Second, after being criticized for his two (boring) performances before UFC 101, Anderson Silva again fought at Light-Heavyweight, this time against the very popular Forrest Griffin.
Griffin is a fan favorite, known for his hilarious quotes and his attack-dog style of fighting. As Round One started, so did the chants of "Forrest! Forrest! Forrest!" Silva quickly answered any questions by dropping Griffin twice in the first round, catching one of his kicks and almost re-doing the James Irvin KO. Forrest charged him again, throwing wild punches. Silva dodged every one of them and connected with a lazy, straight right to Griffin's chin. The fight was over.
A friend of mine often calls Silva the most dangerous striker the world has ever seen. So far, there is no evidence to prove him wrong.