Scenes From a Memory is Dream Theater's worst album, not their best. Most of the CD is sappy songs about "I was once a young woman and I got shot, oh noes..."
As for the best album, I'm tempted to say Iced Earth's Glorious Burden just to spite all the people who mock "that thirty minute Civil War song", but I'll just go with my tried and true favorite CD, namely Draconian Times by Paradise Lost