Jennifer Lopez isn't afraid to throw down. Whether she's at a laser-flecked jungle party (“Waiting for Tonight”) or getting seductive in cyberspace with “If You Had My Love,” the Bronx native has been captivating audiences with her sizzling, blade-sharp moves and high-energy choreography since the late ‘90s. And while “Jenny from the Block” assures us she remembers her roots, “Love Don't Cost a Thing” offers a saturated snapshot into a charmed life.