Considered perhaps the most important producer in history of hip-hop, Dr. Dre's fingerprint is all over much of the genre's classic material. As part of the revolutionary group N.W.A. he and his mates defined gangsta rap. As a solo artist, his "The Chronic" is one of the greatest rap albums of all time and its culutral influence can be felt all over the place. He's also launched the careers of two of rap's greatest, Snoop Dogg and Eminem.