Olivia de Havilland
There’s plenty of them. I’ll throw Jean Arthur out there. Bette Davis was remarkable in carrying her career into her senior years. Meryl Streep is OK, but I don’t like most of her movies, though that’s not necessarily her fault.
GET OUT OF MY HEAD, dammit! How did you know I’d write that?
Keira Knightley and Kate Winslet are on their way to joining this club, too.
Also in to say Kate Winslet; when done, I believe she will be regarded as the greatest actress in the history of film. Greatest. Better than Streep, Bette Davis, anyone.
You’d also be hard pressed to find a bad performance in Cate Blanchett’s IMDB profile.
Ginger Lynn’s still making movies.
Feel that little bump on the back of your neck?..brain-wave transceiver,
Although I think it may be glitchy as nothing else can explain your selection of Keira Knightley 
(Actually I have no idea how good she is as I’ve had limited exposure to her, I agree with Kate Winslet though)
Julianne Moore andDiane Lane are both excellent actresses who become their characters.
For damn sure!
For about 14 years I would say Janet Gaynor.
Streep in a landslide.
Hepburne is second.
Bette Davis probably third.
Then Winslet or Mirren. Dench and Close are, well, close. In the running are Blanchette, Keener, Linney and Emily Watson.
Hmm. May I suggest Love Actually, Atonement, Pirates of the Caribbean, Bend It Like Beckham, and Pride & Prejudice, then, to start.