After 25 years, it's uncanny how many times you can hear the first 30 unmistakable seconds of an AC/DC cut and not be able to distinguish it from any other AC/DC song. Angus Young's agile guitar assaults have always sounded smart enough announcing the band's tunes; it's just that, as catchy as those riffs are, they're rarely a precursor to an interesting, distinct, complete song anymore. There's little doubt that the band's legacy is quite secure by now -- especially when you consider that every primer-gray Camaro in America has a copy of the band's eternal classic, Back in Black, in its tape deck. A spot in the Rock and Roll Hall of Fame likely awaits, and even if the band doesn't get inducted, you can bet Brian Johnson's trademark cap and black T-shirt and Angus Young's schoolboy getup will find a place in the permanent collection. There is, however, doubt as to the creative energy and timelessness of the band's rather obvious heavy metal thunder. They've essentially been making the same record over and over since Back in Black, which was actually good -- unlike the slew of proficient yet dull releases in the years since. Their latest, Stiff Upper Lip, continues the trend of serviceable but nontranscendent rock and roll that makes AC/DC a safe but uninteresting bet. This show, said to be the band's last (as was last year's show at the Gund), will probably thrill the hardcore fans, but the uninitiated are better off getting their kicks elsewhere.