There must be thousands of screamers I've never heard, but I always thought that Roger Daltrey's scream near the end of "Won't Get Fooled Again" was widely regarded as the best, and it's hard for me to disagree. And it's hard to discredit the screamer of the best scream as the best screamer.
It's also hard to ignore Little Richard, and Screamin' Jay Hawkins, even though I totally spaced the latter until reminded.
For best screams, plural, I nominate John Lennon's screaming in Mother.
Lots of good Screamers here but I still think that only Plant and Rodger Daltrey could do it musically (for lack of a better word) with the edge going to Daltrey.
In his prime the power of Daltrey's voice was unmatched in my opinion.
Roger Daltey for me. Also, I thiiiiink he has the best voice of all the old guys. Pretry remarkable.
Paul McCartney cant be overlooked, notbso mucj as the best screamer, but that someone who normally had something of a sweet voice, he could be put up there as, I think, the best all around rock'n'roll singer. Not the best voice, not the best screamer, but the best all around.