After rewatching the documentary chronicling their career, I've been on a major Dream Theater kick, especially for their early albums.
Here for your aural and visual pleasure is one of the band's classic epic tracks: Metropolis, Part 1: The Miracle & The Sleeper. This clip is taken from the final performance of their 20th anniversary tour, recorded at Radio City Music Hall on April 1, 2006, accompanied by the Octavarium Orchestra.
*A note to those who don't like lengthy songs: this clocks in at 10:07*
-TimeChaser
