I'm not crazy about Beyonce's pop40 style music, but the woman <i>can</i> sing, and she's a decent actress.
For those who haven't seen "Cadillac Records", here's a couple of clips of her as Etta James:
All I Could Do Is Cry .. http://youtu.be/dh-0jH4Rb7Y
I'd Rather Go Blind ..  http://youtu.be/N0H-Ed1ddFc