The greatest performances of all time

I did it -- I made my list of the top five performances by actors and top five by actresses. And let me tell you, it was not easy. (Add usual disclaimers about how there are lots of great films I haven't seen, how I may change my mind tomorrow, etc.) I appreciated all the comments on my original post -- they were enjoyable to read and helped me think things through!

So let me give you the lists, and I'll explain a little about my reasoning after that. Going from last to first in each list . . .

( Below the cut )