There's really nothing inherently wrong with -- or even new about -- punk's mainstream popularity. After all, wimpy derivatives of it have been riding the charts since the late '70s, and all it's done is strengthened the resolve of the bands and fans who choose not to buy in or sell out. Arizona's Stereotyperider (playing Saturday, December 18, at the Bluebird) formed in 1999, just as Blink-182's star was ascending, and the group could easily have gotten cute haircuts and pumped out crap like Enema of the State in its sleep. But instead, it's given us Prolonging the Inevitable, a disc that refuses to turn its back on pop punk even as it absorbs and spits out a pure passion for metal, indie rock and hardcore. Past Stereotyperider offerings have floundered a bit in execution, coasting more on integrity than hooks, but this oneis a flat-out triumph. On the song "You're Not Safe With Us," guttural riffs gargle bilious melody and an acid bath of electronic noise as guitarist Mike Upsahl seems to declare jihad on the United States of Mall Punk: "I hope you can deal with all the songs that sound the same." That's definitely a whole lot easier with statements like Prolonging the Inevitable around.