Jennifer Lopez
While there is no doubt that Jennifer Lopez is a triple threat singer, dancer, and actress, with many successful ventures in all three, there is no denying that she is not one of the best singers of all time. She is a good singer, and that has helped her achieve chart topping hits, but these songs are best known for being catchy.
Bret Michaels
Bret Michaels is best known for being the frontman of the band Poison, but more recently he is probably better known for his reality TV stint. While he was a good enough singer to lead the band, he is not known for his vocal abilities in particular.