Anybody from Disney. They're just so annoying, can't make music for crap, and don't even deserve to be famous.
Green Day. Their old stuff was great, like the stuff off of Dookie. After American Idiot was released, the radio overplayed every hit.
Any other pop rock genre artist, like Kings of Leon, We the Kings, Cobra Starship, and especially Metro Station. It's disgusting how they're all covered in tattoos, and think they're so hardXcore, yet the people who listen to their music are usually preteen girls who have no idea of what anything hardXcore is.