In the end, this game will probably be decided by how well LSU runs the ball. If the Tigers can grind away successfully on the ground, Zach Mettenberger will almost certainly eventually find play-action success, and LSU will simply score too many points for TCU to keep up on the scoreboard. But if TCU can keep this game in the teens or low-20s and take advantage of the scoring opportunities they generate, this game is a tossup at worst and a Frog lean at best.
I think LSU has a bit more margin for error, even with defensive inexperience, and I'll give the Tigers the nod because of it. But this game has some fascinating matchups, of both the tactical and one-on-one varieties; and like Georgia-Clemson it is a must-watch, or, since those two games are on at the same time, a must-DVR, at least.