Although a lot of screaming is a turn-off (and pet peeve), some of it I actually like.

For example, I love when Dottie Peoples screams, not that I'm a Dottie fan.
I like Fantasia's style of "screaming" (which is more like what
we call sqwalling (int. sp).
And my favorite of all sqwallers is Adrianne Lewis of Rizen... that chick can sqwall in my CD player any day, any night.
James Hall has a lead vocalist that sqwalls, but I can't remember her name right now... but, I love it.
And there's a male quartet singer who does a LOT of screaming... I'm not into quartet music too much, but I sure love that dude... lol.