Britney. After her, a lot of labels were looking for cute, southern white girls with blonde hair and brown eyes, ala Jessica Simpson, Willa Ford, etc etc
But Beyoncé has her share of clones young and old, like Tamar Braxton.
Obviously Britney. And her clones are more successful, too. Christina Aguilera, Jessica Simpson, Miley Cyrus, Selena Gomez, BoA, Anastacia, Alizee>>>>>Tearria Marie.