Mariah (her use of the different parts of her voice and mid range, and she can still sing live!)
Whitney (the greatest tone and belting voice in history)
Kelly Clarkson
P!nk
Adele
Beyonce (live not studio)
Celine ( she's not really pop though imo)
You should read the vocalist thread on BWB. Whitney partly damaged it because she would go out on stage without warming up. She'd just go out and belt. That's why her voice got darker/heavier between eras (I forget which eras). Beyonce actually warms up her voice which is the proper way to go about things. Also, the bending over and bending back thing that Whit & Xtina do is bad technique. It's trying to force your belts out & that's why they make faces like they're in pain.
There's some other stuff in the thread and it's very informative.
