Here is the best casting for Batman films for me.
Batman/Bruce Wayne- Christan Bale and Micheal Keaton.
To me these two actors brought very different interruptions of Batman and Bruce Wayne, Keaton with the lost Bruce Wayne and tough Batman. But Bale nails both of them with his smooth talk with the ladies (One thing Keaton was lacking) And animal nature of Batman.
Catwoman/Selina Kyle- Michelle Pfeiffer.
To me Michelle brought the sexiness of Catwoman and the physopatic nature of Selina Kyle, and with dazzling chemistry on screen with Keaton she brought the character of Catwoman/Selina Kyle to justice.
Lt James Gordon- Gary Oldman.
Just no words need to describe Oldman`s performance he was brilliant and brought us fans a identical Batman Year One Lt James Gordon.
Alfred Pennyworth- Micheal Gough/Micheal Caine.
Again like the role of Batman these two actors brought different elements to the role. Gough brought his upper class performance of Alfred. Whereas Caine brought his more laid back but at the same time father figure as well as conscience for Bruce Wayne.
The Joker- Jack Nicholeson
Now credit should be given for Jack`s performance as the Joker. With his okay laugh and mean nature as Jack Napier. Jack gave us a dark Joker. But in "The Dark Knight." I hope that Ledger makes the Joker laugh less and more horrific. Like the Joker from the Killing Joke and the early Bob Kane issues of Batman.