Well Scenes From A Memory is my favourite album closely followed by Images And Words. It hs a very interesting concept to it, and is wildly creative.
A Change Of Seasons is my favourite song. Ever. But I wouldn't consider it an album, has The Big Medley on it though, an awesome cover tune (Pink Floyd, Kansas, Queen, Journey, Dixie Dregs, Genesis).
Awake is their heaviest yet, and I love the album, but sometimes I feel like they're trying to be more metal than they are.
Falling Into Infinity, was the producer's blatant attempt at radio success. It has some awesome tracks (Lines In The Sand, Trial of Tears, etc) but it has a lot of filler.
Six Degrees Of Inner Turbulence is too long. I love long songs, but The Glass Prison would be one of their best songs if they cut out the chorus, and all that sample shit, and that riff towards the end that repeats for aaaages.
By the way, Dream Theater are my favourite band...