LOS ANGELES (Reuters) - Slumping music sales left the recording industry with a whopping New Year's hangover, but rap star Eminem (news - web sites) has plenty to celebrate. Reuters Photo Reuters Photo In a year that saw CD sales overall plunge by nearly 9 percent, the Detroit-based rapper-turned-actor sold 7.6 million copies of his latest album, "The Eminem Show," making it the biggest commercial hit of 2002, according to year-end retail figures issued Thursday by Nielsen SoundScan. At the same time, the soundtrack to Eminem's movie debut, "8 Mile," ranked No. 5 for the year with nearly 3.5 million...