by Andy Kellman The lineup of artists on Vol. 30, covering the biggest hits from the tail end of 2008 and beginning of 2009 -- along with the occasional ringer, like Miranda Cosgrove's teen pop single "About You Now," which just barely scraped the Top 50 of the Billboard Hot 100 -- looks like the Now series' version of self-parody. The gang's all here: Nickelback ("Gotta Be Somebody"), Britney Spears ("Womanizer"), Christina Aguilera ("Keeps Gettin' Better"), and P!nk ("Sober"), all of whom have appeared on roughly a third (or more) of the Now discs. And Keith Urban is here, of course, with his ninth appearance since Now, Vol. 12, and it's the sixth time he has closed out a volume. That said, a fair amount of the inclusions -- such as Ne-Yo's "Miss Independent," Taylor Swift's "Love Story," Rihanna's "Rehab," and "Keeps Gettin' Better" -- will likely remain among the artists' most enduring hits. While several tracks are, naturally, more likely to become flashes in the pan (Lady GaGa and Katy Perry come to mind), they are, after all, a major driving force behind the series, part of what makes it a revisionist-proof reflection of popular music.