I'm surprised that I've seen two people question Whitney Houston's voice. All be it, now, her voice is not very good. but in the late 80's and early 90's, she had a perfect voice. Perfect pitch, delivery, tone, runs, belts, transitions, clarity-There was nothing wrong with her voice in the world. listen to this- no one has heard it, but it will knock your socks off!

http://www.youtube.com/watch?v=2aVByaDMpyk

Back then she sounded like an angel to me. I think Aretha might be the best female singer/artist on the planet, but she has a nasal tone.