Pink Floyd

Pink Floyd's masterpiece The Dark Side of the Moon has been selected by the US Library of Congress to be included in its Recording Preservation Registry. The album celebrates its 40th anniversary this month.
The Library motivate the inclusion of The Dark Side of the Moon by saying: "The Dark Side of the Moon benefits from the fact that Pink Floyd worked out the songs in live performances for months before going into a studio. When they did, there were such recent technological innovations as 16-track recorders and synthesizers at their disposal. Rather than overdoing it, The Dark Side of the Moon is an example of brilliant, innovative production in service of the music."
"The album is notable for the close vocal harmonies of Richard Wright and David Gilmour and for the double tracking of voices and guitars. More unusual effects include the flanged choir in 'Time,' the precisely placed delays in 'Us and Them,' and a tape loop at the beginning of 'Money' that was so long a microphone stand had to be used to hold it up."
Other acts that are added to the Recording Preservation Registry in 2013 include The Ramones' self-titled debut, and Chubby Checker's The Twist.