She speaks her mind without too much concern for repercussions, is as much an internet junkie as anyone here (posting interesting links and discussing serious issues, her self-promoting seems to be an afterthought) and seems to love engaging with ideas.
I know her former costar Rose McGowan is more quintessentially ENTP, but I think she could easily be an eNTP, or an iNTP.
I don't think she is SP based on her extensive posting content. Even in the most image-conscious industry on earth, she is drawn more to the abstract and the "what if . . . " and isn't one of those people to mention looks, etc. often at all (not that SPs are that superficial, but as a gorgeous actor whose 9-5 revolves around looks, she seems to not pay much attention to it).