With Dream Theater is it so hard to rank albums, because... the ones I do not enjoy that much, are obviously ones that I don't listen to enough. Listening carefully is the perfect cure to raise the value of an album. Having said, if I had to rank them now, I'll throw them in some groups, to follow a perfect example from the first page.
Good: Falling into Infinity / Systematic Chaos / The Astonishing / Distance over Time
Great: When Dream and Day Unite / Images & Words / Awake / Scenes from a Memory / Octavarium
Brilliant: Six Degrees of Inner Turbulence / a Dramatic Turn of Events / Dream Theater
Perfect: Train of Thought & Black Clouds & Silver Linings
The EP Change of Seasons would be 'good', the song thought, is perfect. If I had to rank live albums, it would be like this...
Good: Live at the Marquee / Once in a Livetime
Great: Live Scenes from New York / Score / Chaos in Motion / Distant Memories
Brilliant: Live in Budokan / Breaking the Fourth Wall
Perfect: Live in Luna Park