When Dream and Day Unite: sorry... don't remember right now, nothing that I found really memorable
Images & Words: Learning to Live ending solo
Awake: probably Voices, tough choice
Falling Into Infinity: Hell's Kitchen or Lines in the Sand
Scenes from a Memory: surprise! Home, but Finally Free (after "we fade away") and The Spirit Carries on are very close
Six Degrees of Inner Turbulence: About to Crash/Goodnight Kiss
Train of Thought: obviously, In The Name of God (the insanely fast one ending the instrumental section)
Octavarium: Sacrificed Sons/Razor's Edge
Systematic Chaos: The Ministry of Lost Souls ending solo, my all-time favourite DT solo
Black Clouds & Silver Linings: tough one, The Best of Times ending solo, A Rite of Passage solo, A Nightmare to Remember short solo after "I'm not one to soon forget..."
Honorable non-album mention: Raise The Knife from Score, it's AMAZING.