One of my friends is a massive Dream Theater fan and he's sent me a good deal of stuff online, which converted me into a fan, but I never had the chance to buy any of their CDs until I was in the US for six weeks (I got back a week ago). While I was there, though, I took advantage of the extremely cheap prices and stocked up: I got six CDs along with the Live At Budokan DVD. Unfortunately, I didn't get Octavarium, but as this thread seems to have been used as a more general-purpose discussion, I'll write about the CDs I did buy.
So what do I think?
Awake is simply one of the best albums ever made. I played it for an entire day without stopping. 6:00 is a sensational album opener, and Space-Dye Vest is one of the best album closers I've ever heard. My other two particular favourites are The Silent Man and Lifting Shadows Off A Dream, but that said, the entire album is superb. I cannot pick a single weak spot.
And everyone should own a copy of Images And Words. Metropolis Part I: The Miracle And The Sleeper is the only non-U2 song in my top ten songs of all time. Besides that, Pull Me Under, Another Day, and Learning To Live are absolute classics. I'd pay the price of the CD just for Metropolis, though.
A Change Of Seasons is also worth the price of a CD alone. I never thought anyone could make a 23 minute long song that doesn't drag at a single point, but Dream Theater did it with this number. A masterpiece.
The other CDs, I haven't had a chance to play as much. Falling Into Infinity definitely seems to be the weakest just from a cursory listen, though I've heard live performances of Hollow Years and Trial Of Tears that are mindblowingly awesome. Train Of Thought has the first Dream Theater song I ever heard, This Dying Soul, and I also really enjoy As I Am, Endless Sacrifice, and In The Name Of God. The last one, I played a lot the day (well, it was night here) of the London bombings.
That leaves Scenes From A Memory as the final CD to mention, and ... goodness, that one really is incredible, isn't it? I need to sit down with the lyrics book and fully follow the story just to properly sort it out in my mind and understand it. I love music that makes you think.