Orbital/YMMV

Fanon Discontinuity: Most fans prefer to pretend that the collaboration with David Gray, "Illuminate", never happened. Some would also deny the existence of the parent album, The Altogether.
Growing the Beard: Their first couple of albums did this for the techno genre.
Tear Jerker: "One Perfect Sunrise", especially since it was supposed to be their swan song.
They Wasted a Perfectly Good Plot: The fandom rejoiced when it was announced Sparks would be collaborating on a track with Orbital. The fandom was disappointed when the result of that collaboration turned out to be "Acid Pants".