Well, probably Pink Floyd - Dark Side of the Moon as well. Although not my favorite album, it is the album I most respect as a crafted masterpiece, and forcing the whole world to listen to it might help give them a better understanding of how to do music and reduce the amount of crude produced by the music industry.
Either that or Genesis' We Can't Dance or maybe Wind and the Wuthering album which are my actual favorite albums to just sit and listen to.