I like every track, but it makes choosing the last option easy, as you get the most music out of it.
I love this outlook, a bit.
That said, Octavarium is a song I've listened to so, so much that it doesn't sound like a song any more. It's just a list of warm noises. And the rest of the album is... really very evenly matched. You know? The Root of All Evil - The Answer Lies Within - These Walls is very close, (I'm listening to TALW right now, and it's so wonderful, and I will never understand its lukewarm reception,) but I might actually go for Panic Attack - Never Enough - Sacrificed Sons. Which, I'm aware, is a vote for Panic Attack over Octavarium, which, I know, that's an act of DT fan heresy, but hey! I do love Octavarium to pieces. It's just that... I've loved it to pieces!