The fighters on my list are ranked by number of KO's in their careers and by who they have knocked out. If a fighter is placed above one with more knockouts, it is because I believe they have knocked out higher quality opponents. 

10. Junior Dos Santos - 8 out of 10 wins by KO. Victims include: Gilbert Yvel, Stefan Struve, Fabricio Werdum and, although it was a verbal submission it was due to strikes, Mirko Cro Cop.

9. Fedor Emelianenko - 9 out of 32 by KO. Victims include: Brett Rogers, Andrei Arlovski, Gary Goodridge and Heath Herring.

8. Robbie Lawler - 16 of 19 wins by KO. Victims include: Melvin Manhoef, Murilio Rua, Scott Smith and Joey Villasenor.

7. Mirko Cro Cop - 11 of 16 wins by KO. Victims include: Wanderlei Silva, Aleksander Emelianenko, Heath Herring and Mark Coleman.

6. Vitor Belfort - 13 out of 19 wins by KO. Victims include: Matt Lindland, Rich Franklin, Wanderlei Silva and Marvin Eastman.

5. Quinton Jackson - 14 out of 30 wins by KO. Victims include: Wanderlei Silva, Chuck Liddell, Marvin Eastman, Ricardo Arona and Kevin Randleman.

4. Mauricio 'Shogun' Rua - 15 out 18 wins by KO. Victims include:Quinton Jackson twice, Chuck Liddell, Mark Coleman, Alistair Overeem and Ricardo Arona.

3. Anderson Silva - 15 out of 25 wins by KO. Victims include: Forrest Griffin, Rich Franklin twice, Nate Marquardt and Chris Leben.

2. Wanderlei Silva - 22 out of 33 wins by KO. Victims include Rampage Jackson twice, Sakuraba twice, Guy Mezger and Mike Van Arsdale.

1. Chuck Liddell - 13 out of 21 wins by KO. Victims include: Alistair Overeem, Randy Couture twice, Renato Sobral twice, Tito Ortiz twice, Vernon White, Kevin Randleman and Jeremy Horn.

Now I know a lot of you may not agree but I feel this ranks these fighters by who they have KO'd and if the victims were in their prime, and how many.