from my daughter, 25 yr old working and living in London:

Ladies - formal context eg in conjunction with gentlemen, or in social
events. If used in work context tends to be condescending. Think Barry
White. Or Alan B'stard.
Women - the generic. Used by men and women, no issues. Just don't overuse it - "people" is to be preferred.
Girls - informal context eg "get the girls to come out for a curry too". Don't use in work unless the girls in your team are using it themselves. Can be used between men in that context.
Females - never ever. Think "creatures" or "the male of the species" as the correct context.
Gals - even more informal and joking, generally used by the old git of the office when joking around.
Birds - the drinking man's reference to the ladies...
Boids - the drunk man's reference to the ladies..
Bitches - ridiculous reference, only to be used in prison situations
Witches - me, nicola and naomi...

(Must-remember-to-stop-using-Gals emoticon)

That gels with my understanding,

Which gender specific words for professions are still acceptable? Usher has been used for both sexes (no more Usherette) for a while now, as has conductor, not that we have them on buses any more. But waiter/waitress, actor/actress and so on? Some of these have generalised in the plural but not yet (in my experience) to the singular. I don't in general like words of the "waitperson" construction. I accept chairperson, but words such as chairman don't signify the male sex to me anyway.

Rod