How do one put a label or tag someone as the king of rap? How do you mix classic rap tracks with today's style of music? Tupac would probably be the most influential rapper of all time, while Eminem holds the record as the highest selling artist. The first “Rap” song to ever hit the radio was a joint called “Rapper's Delite” by a group called the Sugar Hill Gang. Rapping first gained popularity in the U.S. in the 1970s as a kind of street art, especially among African American teenagers. Rap music is cited as the biggest music genre in the world with some of the best selling artists ever. From MC Hammer to Biggie, the Beastie Boys to Eminem, these are the best-selling rap albums to hit music stores.