Which albums have you listened to most frequently over the last year?

[RoeDent]

I've probably listened to Systematic Chaos and Train of Thought most in the past year, as I've purchased those albums in the past year.

[Metropolis Pt. II]

I haven't listened to a lot of DT since January 2016 since I was disappointed with The Astonishing.
However, this year I randomly threw my Awake CD in the car and relived the magic. What a fantastically well-done album.
After they announced Distance Over Time, I decided to do what I've always wanted to do before a release, and listen to each studio album chronologically up until the release date. I'm documenting my thoughts about each album along the way, mostly comparing each release to the prior, seeing how the band evolves. (I've been a fan since 2004 and have all their major releases except OIALT, so none of the music is new to me...just a fresh take on it.)

So far I've just finished SDOIT. I've listened to the first disc multiple times in the past week, so I suppose the answer to the OP's question is Awake and then SDOIT.

[Darkstarshades]

I actually listen to The Astonishing quite frequently.
Probably Images & Words because I'm working on a cover.