That's the last song of the Twelve-Step Suite, isn't it? In that case I'd recommend listening to
the rest of the suite:
The Glass Prison - from Six Degrees of Inner Turbulence. I like the songs on the first CD on the album, they're quite angsty.
I like the second CD too, but I've only listened to the whole song once or twice.
This Dying Soul - from Train of Thought. Pretty much the whole album is quite heavy, you might like that. It was one of the first DT songs I listened to.
Root of All Evil - from Octavarium. I'd really recommend listening to the whole album in one go, I did that in the car a couple of weeks ago.
Every song is in a different key (starting from F) and they added little effects for all the black notes between songs, a very nice touch. :3
Repentance - from Systematic Chaos. Sounds a
lot like Opeth. I think Chris Jericho contributed to the vocals
See also: The Mirror, from Awake. Love that ****.
But since you asked for albums, I think I would start with Octavarium. It's recent enough to reflect the current sound, but almost as well thought-out as earlier albums, such as Metropolis Part II (I haven't listened to it all, but it's QUITE SIK).