Rihanna. Although I'm pretty sure this thread was just created to stir **** up.
I would have voted Christina if it was pre-2008. But I definitely think Rihanna is more versatile and can safely change it up alot and still be successful. It's not so much that Christina isn't the same way, it's just that the general public doesn't want to hear Christina change it up, they want her to stick to ballads.
