Enrique Iglesias + Jennifer Lopez

These dynamic Latin-pop megastars coheadline a dazzling sweatfest. Though both J. Lo and Enrique have recently gone the chart-topping, bass-bumping, party-rapping way by pairing with Pitbull on separate singles, it's the older stuff that gets us going. We can't deny it—sultry dance numbers like "Bailamos" and "Waiting for Tonight" sound just as good as they did in 1999.