If you’d been through the most high-profile breakup in recent memory and made a movie that’s very title (Gigli) has become synonymous with overhyped bomb, you’d probably call your next project Rebirth, too. Yet there’s more to the title of J. Lo’s fourth outing than just wishful thinking. This Is Me … Then, Lopez’s 2002 album, was nearly devoid of any allusions to hip-hop; it was mature, mainstream and dull as a tire iron. Free of that conceit (and Ben Affleck), Lopez has come to her senses and wisely reunited with some of the folks — including hubby Marc Anthony — who made her debut, On the 6, such an of-the-moment pleasure. Rebirth returns Lopez’s butt-shaking sass and produces a quartet of brilliant singles that take the heat off her vocals. The current “Get Right” and “Whatever You Wanna Do” boast bold, golden-age-of-hip-hop beats and hooks. “Cherry Pie” is a Princely, rock-influenced slice of heaven. “Hold You Down” features an irresistibly soppy pairing with Fat Joe that could be “That’s What Friends Are For” for the new millennium. Those songs compensate for the hit-or-miss remainder of the record, including Lopez’s unfortunate Bonnie Tyler impression on “(Can’t Believe) This Is Me.” The desire to show that she’s a timeless star hasn’t left Lopez, but she’s best when she’s reborn with each passing trend.