La Roux's defiant singalong "Bulletproof," the first single from the synth-pop duo's self-titled 2009 debut, sold more than 1.7 million copies, according to Nielsen SoundScan, and peaked at a surprising No. 8 on the Billboard Hot 100. Follow-up single "In for the Kill" finds androgynous frontwoman Elly Jackson showing off her crystal-clear voice over producer-behind-the-curtain Ben Langmaid's minimally styled analog beats. "Kill" may not be as catchy as "Bulletproof," but it shows that this Eurythmics-recalling twosome's defining qualities-her power-elf voice and his '80s sonics-can stay fresh from song to song. A stripped-down dubstep remix by producer Skream is popular in the United Kingdom and was featured during an Aug. 8 episode of "Entourage," proving that Jackson is already a preferred voice of that rumbling underground dance style.