I agree with Helmet, and HEYNOW - I tend to like more hardcore; but you can't deny her success as a singer, and performer. Most of her music is catchy; whether you want to hum it, or not. She is contraversial - As most everyone that I admire is. And, she does use her success in ways that benefit others. Like her, or not; you have to appreciate her, or you're lying to yourself.
I am more towards Megadeth, Dream Theater, Buddy Guy, Tora Tora, NWA, SSSC.