Went with "Breaking All Illusions". Yeah I know, I'm pretty surprised too, but being half the length of "Octavarium", it really gives a harder punch to me. 8VM is a slow-cooker and I need to be in the mood to listen to it, usually after listening to the rest of the album before it. BAI can just be popped in at anytime and I can enjoy it.
Octavarium was my first NEW DT album after I became a fan, so I have a special place in my heart for that album, and it has aged pretty well with me, but I will admit that there have been some really good DT songs SINCE then, and BAI edges out the title track of 8VM.
-Marc.