4. Pink Floyd - 'Dark Side of the Moon'
Pink Floyd's Dark Side of the Moon is one of the few prog albums loved by rock fans outside of the prog community. Songs like "Time" and "Money" stand on their own as more traditional rock songs, though they're really part of a longer opus about greed, death and insanity. The album continues to speak to teenagers all across the world, pretty much making sure that David Gilmour's great-great-great-great grandchildren won't have to work a day in their lives. Note: no matter what you heard on the playground in the seventh grade, the band didn't record the album to line up with scenes from The Wizard of Oz. The few scenes that do line up are just a coincidence, and proof that if you look hard enough for something, you tend to find it.