Guess I'm in the minority about Faith Hill. She tops my most disliked female singer because of her totally classless response to LOSING an award to Carrie Underwood.
There are so many that it is hard to narrow it down. With this disclaimer: I hate any of the thug, moronic attempt to rap. That said, I can listen to Kid Rock, Ice Tea, The Beasties, etc in small quantities.
Kanye West (wouldn't know one of his songs if I heard it but he has to be one of the most classless individuals walking the earth).
Oasis ( who once claimed that they would be bigger than the Beatles. Another totally classless act)