Yeah, I know the OP said 1 song, but there are way too many for me.
This list is only a small amount of music that I don’t get sick of.
Prog:
Yes - Close to the Edge, Gates of Delirium, And You and I
King Crimson - Starless, Exiles, Book of Saturday, Lark’s Tongues in Aspic
Premiata Forneria Marconi - Per Un Amico, Dove... Quando... (Parte I and II), L’Isola di Niente
Genesis - Dancing out on the Moonlit Knight, The Lamia, Super’s Ready
Magma - Köhntarkösz Anteria (all 3 parts)
Gentle Giant - Knots, In a Glass House, Proclamation
Anglagard - Vandringar I Vilsenhet (Wanderings in Confusion)
jazz:
Mahavishnu Orchestra - Eternity’s Breath
John Coletrane - A Love Supreme
Return to Forever - Duel of the Jester and the Tyrant
Bruford - Fainting in Coils, Travels with Myself - And Someone Else, Beelzebub
Oregon - Waterwheel, Yellow Bell, Vessel
Allan Holdsworth - The Un-Merry-Go-Round, Three Sheets To The Wind
Pharoah Sanders - Black Unity, You’ve Got to Have Freedom
Classical:
Joan Tower - Concerto for Orchestra (1991), Silver Ladders (1986)
Elliott Carter - Variations for Orchestra (1955), Concerto for Orchestra (1969), Three Illusions for Orchestra (2004)
Charles Wuorinen - 4th Piano Concerto (2003), Iridule – for oboe and six players (2006)
Unsuk Chin - Violin Concerto (2001)
Magnus Lindberg - Sculpture
