6. "Hollaback Girl" (2004)
Stefani's solo career was already off to a good start thanks to the first two singles off Love. Angel. Music. Baby., but the stomping banger "Hollaback Girl" solidified her new pop reign. Written with assistance from the Neptunes, the semi-ridiculous single that taught everyone how to spell "bananas" was a response to Courtney Love calling Stefani a cheerleader.