After the roaring success of Wide Open Spaces--a blend of turn-of-the-century pop and country traditionalism--what do you do for an encore? Rather than deliver more of the same, the Chicks have chosen instead to up the ante in country radio with a follow-up that's both poppier and twangier than its predecessor, and just plain better too. Some of it we've heard before: "Hello Mr. Heartache," for example, adheres pretty closely to the honky-tonk model of "Tonight the Heartache's On Me." Mostly, though, the record lights out for new territories. "Without You" is driven by an in-your-face string arrangement that's downright fierce, and the rootsy "Sin Wagon" may rock harder--and with more solos--than any mainstream country since Buck Owens held forth. That's not to say Fly's perfect. A couple of songs miss the mark, particularly "Goodbye Earl," an abusive-husband murder song that's sure to get criticized (wrongly) for being anti-male but actually fails because it can't decide if it's a moral lesson, a horror movie, or a joke. Still, even in this failure, the Chicks are bravely pushing the envelope. If they push hard enough, maybe Young Country radio will open up some wider spaces. --David Cantwell