The post-Norah Jones phenomenon of standards albums by singers who don't usually sing them has yielded the occasional alternate-universe proposition: Cyndi Lauper doing "La Vie en Rose"? Hey, middle-aged mothers just wanna have fun, too. Country vet Merle Haggard isn't the least likely artist to rip through the Great American Songbook. (My vote? Queen Latifah--if she hadn't just released the perfectly middlebrow The Dana Owens Album.) But on Unforgettable, Hag's voice, a tarnished whiskey-sour croon with all manner of rough edges, doesn't lend itself to easy piano-bar interpretations of "As Time Goes By" and "Pennies From Heaven." This is a good thing: Too often we're unable to hear anything in these songs beyond our collective memory of them--that's the risk in establishing a canon. Yet Haggard gives these tunes a proud sense of experience that has less to do with the sophisticated facility of producer Freddy Powers' smooth country-jazz settings and more to do with the sound of a man flipping through his back pages at a leisurely pace you couldn't hurry if you tried.