In the middle of his song "Spit It Out," Brendan Benson declared "for every bubble you blow, I'm gonna pop it." The line offered a pretty good insight into the singer-songwriter's methods. For all his unstoppable power-pop moves and clear-eyed, harmony-enhanced bubblegum tunes, a bittersweet current runs through his best work. Songs of busted love and romantic indecision get dipped in a chocolate so sweet that it's easy to miss the pathos: His songs are catchy but rarely fluffy. Last night's sho