Ever since breaking into the mainstream with 2003's Elephunk, these hip-hop champs have been all about the whoosh factor. With will.i.am behind the block-rocking beats and dance-floor jams while singer Fergie nails addictive hooks at maximum volume, the group soundtracked '00s pop hedonism with instant party-starter “Let's Get Retarded” and bump-and-grind nugget “My Humps”. As the decade closed out, they embraced electro-funk and EDM, adding more digital oomph to the likes of “Rock That Body” and “Boom Boom Pow”, songs that do exactly what they advertise in their titles.