Here's what I would do for Catwoman.
Selma Blair (aged 5 years through makeup for the "last of her 9 lives" thing. One grey streak in her hair, which is cut short.)
Black T-Shirt + jeans plus leather jacket.
Night-vision goggles for a mask.(May or may not slightly resemble cat ears on the top."
Batman-esque utility belt.
Basically, an expirenced cat-burglar with gadgets. But, this is just my opinion and I'm constantly refining it.