6. The Beatles, 'Rubber Soul' (1965)
Rubber Soul was a transitional moment for the Beatles as they transformed from a pop group mixing covers with sleek, catchy originals into an album-oriented, artful rock band. The LP fused folk with R&B into an atmospheric and tender collection. With Martin at the boards, the same producer who helped them become the biggest hitmakers in the world also oversaw their most mature turn yet.