The xx is a trio of Londoners whose eponymous first album, released in 2009, has defined the way pop music sounds today. I remember knowing, when it came out, that I was listening to something both distinctive and familiar, which is usually an indicator of success. The schtick was to plunder various music canons which they were way too young to have heard first hand — Nineties house and rave, lachrymose mainstream Eighties synth-pop, angst-ridden shoegazing — strip it down and mix it all up with very clever beats, provided by the genuine talent of Jamie Smith.