A diva, as defined by Beyonce, “is a female version of a hustler.” And though there’s no denying B’s claim in her new single, “Diva,” that she’s “been the No. 1 diva in this game for a minute,” you certainly can’t knock Rihanna’s hustle in 2008. After scoring four hit singles with 2007’s Good Girl Gone Bad, her third CD in less than two years, she re-issued the disc last summer with three sizzling bonus tracks (”Disturbia,” “Take a Bow,” “If I Never See Your Face Again”) that quickly soared up the charts as well. Now, after honing her live act on the road with Kanye West’s Glow in the Dark extravaganza, and more than a year after Good Girl’s original release date, Rihanna remains on the charts with her eighth single, “Rehab,” featuring Justin Timberlake, plus a cameo on T.I.’s “Live Your Life.” For a pop star who was once dismissed as being incapable of yielding more than one hit song per album, Rihanna’s newfound staying power is nothing short of remarkable–and proof that there’s room for more than one diva in this game.