I've been running this series for several years now, and there are still plenty of songs that could be featured here. When I think about overly long songs, I always come back to one song in particular: Sister Ray by The Velvet Underground.
Even in 1968, it wasn't exactly common to write longer songs, so it was surprising that this band recorded a song that was more than 17 minutes long. The early Velvets' songs were always at their best when they were built on a simple basic structure. Thus, “Sister Ray” developed from a very simple funk riff into seventeen minutes of sparse sound structures of incredible complexity.
What makes the song so special is the interplay between a simple riff, John Cale's Vox organ, Lou Reed's vocals, and Moe Tucker's drums. Sister Ray builds momentum minute by minute into a frenzy that seems to end only to pick up speed again. A masterpiece that has rightly served as inspiration and motivation for many subsequent musicians.
The Velvet Underground - Sister Ray