^ I think Itsuky is a gaga fan too. The avatar is towards the thread starter? I do agree with Taylor Swift. I enjoy her music, but you'd have to pay me to see her live in concert.
Well, there are plenty of singers whose music I really enjoy, even if I can't speak much for their voices. In my opinion, I'd have to say that I don't think Heidi Montag, Ayumi Hamasaki, or Rihanna are very good singers at all. I also have a love-hate relationship with Christina and GaGa's voices. It's not so much that they can't sing (because they can), but sometimes the overall tone grates my eardrums.
I don't think there are really any 'terrible' singers.
Taylor is okay, not the best but definately not the worse.
Justin can sing.
All of the Beyonce and Gaga in this thread, I can't.