With first-week sales of just over 784,000, rock legends AC/DC’s latest LP, Black Ice — which was sold exclusively in the U.S. through Wal-Mart, Sam’s Club and the band’s official Web site — has earned the distinction of becoming the year’s best-selling rock debut, surpassing the 721,000-plus week-one sales put up by Coldplay’s Viva La Vida or Death and All His Friends. Lil Wayne’s Tha Carter III, which sold over a million units its first week in stores, remains the year’s best first-week seller.