18. One Direction, 'Four'
When you are the world's biggest boy band, sometimes you get a surprising amount of freedom. On Four, One Direction honed in on their classic rock chops at a time when pop has been leaning more into the spheres of hip-hop and R&B. For these boys — folky, wistful, dripping with young romance — it works without sounding anachronistic. When not culling inspiration from the Fleetwood Mac songbook (like on the Rumours-lite "Fireproof") 1D sounds a little reminiscent of early millennium indie rock, as heard on album highlights "Stockholm Syndrome" and "No Control." Though last year's Midnight Memories was their claim to adult maturity, Four is the sound of the group settling into it. B.S.