Don Firth said "she doesn't just play Nicole Kidman playing the character she's portraying (if you can follow that). That's something I tend to associate more with British actors (able to play a broad range of characters—see Judi Dench) than with Americans (usually keeping to a narrow range; e.g. John Wayne never played anyone but John Wayne),"

Although I agree with you, I have frequently had problems with some of the more famous British actors intoning their lines in a plummy, artificially-mellifluous kind of "look at me, I'm a famous thespian" tone. Specifically, I always noticed that in Olivier, and more recently in Ben Kingsley, particularly his performance in The House of Sand and Fog.

I agree that some American actors have a very narrow range, and are therefore typecast -- John Wayne always played John Wayne.