As the host of MTV's entertaining Pimp My Ride, Xzibit's stock has risen as a celebrity, even as it recedes as a rapper. His latest album, Weapons of Mass Destruction,isn't generating much of a buzz, probably because many of its tracks are perfunctory, addressing hand-me-down themes like "Ride or Die" and "Saturday Night Live." And those are the good songs; others just seem to play aimlessly like long stretches of aural wallpaper. They leave the impression that Xzibit's time is passing; the hungry MC who once screamed on "Paparazzi" has turned his attention to other matters. "Lately, I've been feeling like Will Smith," he admits on "Criminal Set." "Why bother with rap when I can get twenty mil for a flick?"