I understand that there is still one big event left (UFC 168), but I thought it would be great to get this discussion started early.
Who do you guys think is the 2013 fighter of the year? There have been some incredible candidates this year. My list (in order) is below:
 Vitor Belfort
defeated Michael Bisping by KO (head kick in the 2nd round at 1:27)
defeated Luke Rockhold by KO (spinning heel kick in the 1st round at 2:32)
defeated Dan Henderson by KO (head kick in the 1st round at 1:17)
 Demetrious Johnson
defeated John Dodson by unanimous decision
defeated John Moraga by submission (armbar in the 5th round at 3:43)
defeated Joseph Benavidez by KO (punch in the 1st round at 2:08)
 Urijah Faber
defeated Ivan Menjivar by submission (rear-naked choke in the 1st round at 4:34)
defeated Scott Jorgensen by submission (rear-naked choke in the 4th round at 3:16)
defeated Iuri Alcantara by unanimous decision
defeated Michael McDonald by submission (guillotine choke in the 2nd round at 3:22)
 Robbie Lawler
defeated Josh Koscheck by KO (punches in the 1st round at 3:57)
defeated Bobby Voelker by KO (head kick and punch in the 2nd round at 0:24)
defeated Rory MacDonald by split decision
I think Vitor stands above the rest because he faced three clear top 10 fighters, and in all 3 fights, I would say most picked against him. Not only that he finished them all, all with head kicks, and with him looking better in each fight and finishing his opponent faster than the previous.
Weidman is already an honorable mention even if he only had one fight as he beat the seemingly unbeatable Anderson Silva. If he manages to do it again and even more impressively, he easily makes this list but I still put Vitor ahead of him.