Rihanna for me. I've never been a big fan of Beyonce. Beyonce sings good, but truthfully she just sounds like a whole lot of other singers in her genre. I don't think she stands out that much, honestly. And even more honestly....I always thought Kelly Rowland was a better singer than Beyonce strictly becuase she sounds different from the rest of the pack. Likewise for Rihanna....she just has a different sound, and she's also versatile.