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.