Agree with most of those submitted, but especially these:
Barbara Stanwyck as Phyllis Dietrichson in Double Indemnity.
Claire Trevor as Helen Grayle in Murder, My Sweet.
Jane Greer as Kathie Moffat in Out of the Past.
Lizabeth Scott as Dusty Chandler in the underrated Dead Reckoning.
Kathleen Turner as Matty Walker in Body Heat. Probably my Number One.
Linda Fiorentino, The Last Seduction.
Virginia Madsen, The Hot Spot.
Not sure about Audrey Totter, Gloria Grahame and Marie Windsor as "Femme Fatales." Maybe bad girls, but not quite devious or evil enough.
One of the interesting things that shows how good these women are/were as actresses is that they are totally believable in good girl, bad girl and femme fatale roles.
Compare Jane Greer in Out of the Past with Robert Mitchum and Jane Greer in The Big Steal with Robert Mitchum two years later. Not to mention dozens of roles with Stanwyck.
Occured to me that this would be a suitable thread for General Discussions, since Femme Fatales also exist in mystery, suspense, drama, etc.?