Actress seems less condescending than lady actor, to me. "Lady Actor" or when they refer to, say the boys' basketball team as "the bulldogs" and the girls' basketball team as "the lady bulldogs", it seems extra sexist. "Even though they're doing a man's job, they're still Ladies with perfect manners, manicures, and coiffed hair." And saying Helen Mirren is one of the "best lady actors" sounds to me like what they're really saying is she's not bad at this whole acting thing, you know, for a woman.
oh, hello soapbox. I didn't see you there.