Just saw "Captain Blood" the other night for the first time, and I was surprised how good Errol Flynn was when he was young, before he got mannered.
As I have said before, Mia Farrow as Daisy Buchanan in the Great Gatsby is my low. Robert deNiro as the Frankenstein monster in Branagh's Frankenstein was pretty close.
I am told that Nicole Kidman (wearing a prosthetic nose) is coming this Christmas as Virginia Woolf in "The Hours". This could be a new one for the list.
On the other hand there are some recent films with unerring casting -- Harry Potter seems to me to be just about perfect, even though I personally retch at the thought of Richard Harris.
yours, Peter T.