SUGARLAND For a band that consistently tops the country charts, the slick duo Sugarland sure is doing a good impression of a pop/rock act - and lately it's with mixed results. Aside from Jennifer Nettles' sultry Southern drawl, little remains of the emotive, rootsy balladry that first made she and guitarist Kristian Bush darlings of the modern country scene. Last year's release, The Incredible Machine, left even die-hard fans scratching their heads with its heavy-handed arena rock anthems. But the pairing of Nettle's powerhouse, soul-drenched vocals with new danceable rhythms shines where it's intended - on a big, bright stage full of big-screen razzle-dazzle. $25-$80. Verizon Wireless Amphitheatre.