Ocean Machine is more than likely my favorite Devin Townsend album. Terria is definitely near the top, along with Synchestra. I love all of them really. I've been spending the last day trying to figure out how I would rank the DTP albums in comparison to each other, and I'm finishing up listening to all four of them right now, and I couldn't even tell you which one I like the most, or least.
I like them all for different reasons, because they're all different. Every album he's ever released. That's why it's so hard to put numbers on them.
I've lost track of just about everything.