A band which was founded in 1985, whom achieved mainstream success with their single "Creep". I wouldn't consider them pop rock or particuarly mainstream but my generation doesn't really listen to radiohead much. They focus on depression and other interesting aspects of life. They surprisingly can be relaxing. They're unique in their style. I'd put them with The Clash and Nirvana.
Person A "I just listened to some Radiohead, so relaxing"
Person B "Who the f*** are Radiohead"