MINNEAPOLIS (AP) - Best Buy Co. has lost another executive closely involved with its effort to focus on its most profitable customers. Michael Keskey, president of Best Buy's U.S. retail stores, left the company for personal reasons after more than a decade, the company said in a regulatory filing on Tuesday. In September, executive vice president of customer segments Philip Schoonover left to become chief merchandising officer for Circuit City. The two were Best Buy's top executives charged with carrying out Best Buy's "customer centricity" strategy, a program focused on identifying and targeting the most lucrative customers at Best Buy,...