It shouldn't surprise anyone to see Anderson Silva at No. 1 on this list. Silva won the title at UFC 64 in 2006 in his second UFC fight. Silva scored the win over Rich Franklin at 2:59 of the first with a TKO due to knees from the Muay Thai clinch.
Silva then submitted Travis Lutter with a triangle choke in the second round, but that wasn't a title fight as Lutter had missed weight.
Silva's first official title defense came against the former King of Pancrase, Nate Marquardt. Unfortunately, Nate wasn't so great that night as he was TKO'd at 4:50 of the first round.
Next up for Silva was a rematch with Rich Franklin in Franklin's hometown. That didn't matter to Silva, as he scored another TKO with knees, this one in the second round.
Silva then faced the former Pride welterweight and middleweight champion, Dan Henderson. Silva unified the Pride and UFC titles as he scored a second-round submission by rear-naked choke over the former Olympian.
Silva's next title defense came against Patrick Cote at UFC 90 in 2008. Cote was the first person in the UFC to make it to the third round with Silva, but a knee injury early in the third forced an end to the fight and gave Silva another TKO victory.
Silva then faced Thales Leites, who had been on a five-fight win streak with three submissions. Silva went the full five rounds with Leites and took a unanimous-decision victory (49-46, 48-47, 50-46).
In Silva's next defense he faced Demian Maia, and many fans may remember the debacle that fight became. After easily winning the first three rounds, Silva took to clowning Maia and didn't fight very much. In the fifth round he was admonished by the referee, but it was too little too late. Silva would take the unanimous decision with scores of 49-47, 48-47 and 49-46.
Silva then had the toughest fight yet of his career as he faced Chael Sonnen at UFC 117. Sonnen dominated every minute of that fight, but wasn't able to see it to the finish as Silva locked up a triangle choke and armbar to score the submission win at 3:10 of the fifth round.
Silva's next fight was much easier for him, as he knocked out Vitor Belfort with a front kick—a first in the UFC—at 3:25 of the first round.
Silva's next fight was a rematch with Yushin Okami. Silva and Okami had previously met in 2006 before either was in the UFC. Okami won that fight by DQ after Silva delivered an illegal upkick from his guard which nearly knocked Okami out. Silva won the rematch by TKO at 2:04 of the second round.
Silva had another rematch in his next fight, as he faced Chael Sonnen for a second time. This one was far different from the first fight though. Sonnen won the first round easily, but after throwing a spinning backfist and falling down, Silva capitalized and hit Sonnen with a brutal body shot, eventually leading to a TKO victory for Silva at 1:55 of the second round.
That was Silva's final successful title defense, as he lost the belt to Chris Weidman by knockout in his next attempted defense.