Too many great bouts to pick just one. I was leaning towards some Gracie action, but I do like some of the newer and in-between fighters as well. I can say this, no fight at UFC 118 would qualify. I got free tix to that, and it sucked ass. I literally almost fell asleep watching a couple of the fights that night.
I used to like Tank Abbot, but as the sport progressed towards more structure people realized the guy was just tough enough to take a beating and keep throwing punches and elbows. He never had any real fighting skill. I'm not saying I would fight him, even now...but I know people 1/4 his size that would have him knocked out and broken in less than 30 seconds.
As for Brock, he's close to the same path...but, he is actually getting more skilled with each fight. That pink-haired kid got lucky as shit, plain and simple. I would have demanded a rematch with anger and fury if that was me, and then let the kid know his show was over.
Nowadays, I try to catch any fights with those I like to watch: Brock Lesnar, Liddel, Faber, Henderson*, GSP.. I put the * next to Henderson, because well..he just got KTFO off the fence.. still a good fighter, but not a good fight for him...