Gonna try and limit myself to a few, though I realize now many of these are 21st century when I thoroughly began my theatregoing...
Have to second Fiona Shaw's Medea with the person who brought it up above. Absolutely mesmerizing.
I would watch Mercedes Ruehl read the phone book, but her Stevie in the original cast of 'The Goat' still haunts me, especially her final tableau. (Not to knock Turner, who I'm sure will do a terrific job, but I was really pulling for Mercedes to be Martha in the 'Woolf' revival. C'est la vie).
And I have to think about it some more...but I think I need to nominate Peter Dinklage's Richard III as one of the first (official) great 21st century perfs. Really mesmerizing work.
Will try to consider more that are more fitting in the topic timeframe.
-Joe T.
Laughing is a tonic. So forget crying. Cry, and you cry alone. Laugh and you...cry alone later. And remember --- always breathe. Even if I stop, you keep breathing out there, alright?