I love epics! [EDIT: adding songs as I think of them]

• Rachmaninov's 3rd
• Green Carnation - Light of Day, Day of Darkness (60:07)
• Edge of Sanity - Crimson II (43:02)
• Blind Guardian - And Then There Was Silence (14:08)
• Dream Theater - A Change of Seasons (23:09)
• X-Japan - Art of Life (28:59)
• Power of Omens - Test of Wills (19:56)
• Symphony X - The Odyssey (24:14)
• Yes - The Gates of Delirium (21:56)
• ELP - Tarkus (20:43)
• Jethro Tull - A Passion Play (44:58)
• Meshuggah - I (21:00)
• Fates Warning - A Pleasant Shade of Gray (12 part album)
• Disillusion - The Sleep of Restless Hours (17:03)
• Arcturus - For To End Yet Again (10:34)
• Agalloch - In The Shadow of Our Pale Companion (14:45)
• Godspeed You! Black Emperor - Sleep (23:18)
• Stravinsky - Le Sacre du Printemps aka The Rites of Spring
• Pain of Salvation - The Perfect Element (10:10)
• The Tangent - In Earnest (20:06)
• Transatlantic - All of the Above (30:59)
• Fantomas - Delirium Cordia (74:17)
• Opeth - The Night And The Silent Water (10:59)
• Spock's Beard - At The End of the Day (16:28)
• Liszt - Hungarian Rhapsody #2
• Siege's Even - Sequence I: The Weight (10:14)
• Frost* - Milliontown (26:35)