51. Miles Davis, Kind of Blue (Columbia/Legacy, 1959)

Simply put, if you buy one jazz album, this should be it. Greying genre historians go on and on about how this record introduced the concept of modal jazz (where the overall key instead of chord changes determines the solos), and the line-up (featuring John Coltrane and "Cannonball" Adderly) is a killer. Unquestionably the pinnacle of cool jazz, but what's really significant is how it does so much with so little. The average track lasts nine minutes and consists of a minimalist vamp that repeats, makes room for a solo or three and occasionally moves up or down a note on the scale. But I've always been struck by the mood this album creates. Not really blue per se--more bluish-greenish-violet, caught in a venerable, hypnotic buzz that's calm, not tense. I respect how Coltrane pushed the polytonal sound barrier on his later recordings, but I really admire and love this record for how quiet it is.