This decade had some big punchers. Wlad was definitely the hardest puncher of that decade in absolute terms. But how do we even compare HWs to lower weight class guys pound for pound. So I'll leave him out of this for this discussion. Pacquiao is the hardest hitter of the 2000s pound for pound. Name me one Flyweight champ could knockout a 2009 version of Cotto. No Flyweight in history has that type of power. Hell, even the massive punching, natural 140 pounder, Randall Bailey was decapitated by Cotto. And Micro-Pac annihilated him Cotto. Also, for what it's worth Ricardo Torres could really bang too. Cotto was routinely matched with huge bangers. Name me one other Featherweight in history who could stop a 2003 version of Barrera? Naseem Hamed landed flush a couple times on MAB. And despite his repuatation as a huge puncher, Barrera didn't even flinch when Hamed landed. Pacquiao dropped MAB with 1 left hand. And hurt him so bad Barrera's brother jumped into the ring crying. Against Marquez, Pacquiao rose up in weight to fight a career Featherweight. A guy who was never stopped, even against Welterweights and Lightweights. And Pac dropped him 3 times in the opening round. With just a single straight left hand. Pac had Morales hurt again in the opening round with a single left. Morales was doubled over in agony and only his tremendous heart kept him going. Then Pac stopped him in the rematch. He even made Morales back up and retreat and disengage. And nobody and I mean nobody, backs up Morales and makes him run. He iced Ricky Hatton with 1 shot in the middle of the ring. He hit that poor soul so hard that he was forced to hyperventilate on his back, so that he didnt die. The man rose from Flyweight to end Margaritos career and break his face. Name me one other Flyweight who could beat the daylights out of Margarito. Honorable mentions include Edwin Valero, David Haye, Kelly Pavlik. All these guys were big hitters, but none could stop, hurt, drop and destroy the caliber of fighters Pacquiao could. And none could rise up the weights like Pac. Although I must say Haye rocking Valuev was impressive. I could see the argument to be made for Tito Trinidad being the biggest hitter of the 2000s pound for pound. He had shocking power, that left hook was bone shattering. The way he moved up to 160 pounds and savaged Joppy that easily was incredible. And you could tell that wasnt his natural weight class at all. He was looking soft and skinny at 160 pounds. The guy truly had special power. But I'm gonna give it to Pac.