For me probably
Thomson/Melendez 2
Thomson/JZ Calvan
Diaz/Daley
Yours? 
Way to take all the good ones
Fedor/Hendo
Healy/Beerbohm
Lawler/Manhoef
Of course, Diaz/Daley is the best though.
Hendo vs. Feijao
Wow, there are so many. YOu guys took them all.
Diaz v. Daley. Best MMA round in the promotion's history.
Tate/Kedzie was the best women's fight I've ever seen.
Diaz/Zaromskis
Woops. Le vs Shamrock
Cormier Vs. Barnett
Diaz Vs. Daley
Diaz Vs. Zaromski
Melendez Vs. Thomson Triliogy
Rousey Vs. Tate
Shields Vs. Hendo
Werdum Vs. Fedor
Fedor vs Rogers was insane to me! The way Fedor got roughed up and then came back with that big right hand? Damn!