Ranging from the genre's earliest groups to modern-day stalwarts, we count down the best of the best.
Featuring Vangelis and Demis Roussos, the album still inspires wonder decades after its release.
With partner Daevid Allen, Smith formed the first incarnation of Gong in 1967.
In 1977, the group saluted what would become the longest-running TV football show in the world.
