MMA's 10 best pound-for-pound fighters

This is an unexpected update, to say the least.

After all, UFC 112 was supposed to be fairly status quo, marked by two straightforward and easy title defenses for pound-for-pound stars Anderson Silva and B.J. Penn. In actuality, "The Spider" turned in a positively surreal performance, which sparked enormous debate over his psyche, desire to compete and status as the sport's top fighter. As for Penn, a more-competitive-than-expected bout with Frankie Edgar went from pleasantly surprising to all-out shocking when "The Prodigy" lost a unanimous decision on the scorecards.

Penn's fall makes the lightweight division vastly more intriguing in the immediate future. For the first time in quite a while, there arises a legitimate debate as to who can call himself the true king of a particular weight class. Better still, three of these pound-for-pound entrants are in action in the next two weeks, including Dream lightweight champion Shinya Aoki, who meets Gilbert Melendez for the Strikeforce crown on April 17. Will we get lightweight clarity in Nashville?