Randy blythe from lamb of god...loved his voice since Burn the Priest days...
Loads of people can scream, consistent and brutal even. But Randy Blythe takes the cup for being the most versitile screamer/growler with the most control. :/ (of all the bands I heard so far la, which isn't many)
You can actually hear the lyrics when he screams. In the new album anyway, cause black label is like.. YA YA YA YA YA YA YA!!!
Other notable screamers I love are :
Mark Hunter - Chimaira (The Enemy, scream + audible lyrics = hard to achieve)
Angela Gossow - Arch Enemy (female sia... but actually shes more of a growler)
and who can forget Buddy who was in Senses Fail singing 'The Irony Of Dying On Your Birthday'
The first line was : Just know, we are, a spec, in time..
during the 'we are' part.. the are started as a growl, then a shout, then a shriek, not progressively, it was like a 3 part thing. Damn nice! All screamo-emo-whatever-music-core fans go check it out
He sucks live though.