Interestingly he mentions Carey Mulligan and Daniel Craig have been cast although there is no official confirmation about it.
I suppose at its base this is a police procedural (although the police are on the wrong track all along). But Lisbeth and Mikael are quirky individuals and make up their detective work as they go, so it's hard to predict the story arc. It's also an advantage that the actors are not conventional star types. That will be the tricky part in the Hollywood versions. Carey Mulligan and Daniel Craig have been cast for David Fincher's 2012 remake of “Dragon,” and they're very good, but are they too mainstream? How about, oh, say, Ed Norton and the non-"Twilight" Kristen Stewart?