Brock Lesnar - Clipping Randy in the back of the head, that was sweet. (I don't like the guy much, but you can't deny he's becoming a solid fighter).
Machida - His trip of Thiago early in the fight, the first time he trips him and takes him down. It's not a huge thing, but everytime I see it, I'm very impressed, it just looks so awesome.
Silva - The last shot of the Forrest fight, and the entire Leben fight.
GSP - his leg trip of Matt Hughes in their second fight, I can watch that many times over.
Penn - His RNC of Kenny, mainly because I'm not a fan of Kenny and I loved him sinking in that choke against a guy who thinks he is above the rest in BJJ and was supposed to have this ground game that can handle BJ because of his win over Stevenson.