Like I mentioned earlier and some people don't seem to understand, its completely SUBJECTIVE. You could make a compelling arugment for Texas, Oklahoma, or even Texas Tech.
Personally, based on the merits I assigned, I think Texas should go. Sorry, getting blown out by 44 in November when you're ranked #1 in the country eliminates you in my book. Losing a tight one on the road and beating OU means more to me than blowing out someone at home and losing at a neutral site to Texas. I could care less what these two teams did against Missouri because you could then bring up every common opponent played. I could turn it around and say that UT beat Kansas by a larger margin of victory than OU. I'm not gonna deal with that. It was only a 3 way tie and the debate should be left to how the three teams did and the way they played in those head to head matchups. That's my criteria.