Having Jolie as Catwoman would be a mistake. People won't be seeing Catwoman on the screen, they'd be seeing Angelia Jolie. Basically, it'd be repeating some of the issues people have with the Burton/Schumacher films. If Catwoman is used, I suspect it'll be played by someone we least expect.
That's what I'm thinking, but I also remember when Heath Ledger was announced to play the Joker. I had the exact same thought. And look how that turned out...