Eric Bana as Bruce Wayne/Batman
He could pull off the action, and has comic book movie experience. I casted Thomas Jane as Batman in my Justice League fancast but I think he can only do a good Batman, so I went with someone who could pull off Bruce Wayne and Batman, that's why I chose Eric Bana.
Michael Caine as Alfred Pennyworth
Perfect for the role. Nuff said.
Gary Oldman as Commissioner James Gordon
Couldn't think of a better choice.
Eva Mendes as Renee Montoya
Although Michelle Rodriguez is a fan favorite for the role, I feel that they would be type casting her if she is ever picked for the role. So I went with a different Latino actress who could pull of the sexiness and personality, so I went with Eva Mendes.
Logan Lerman as Dick Grayson/Robin
I'll admit, I'm not the biggest fan of Robin, but if they ever cast Robin in a Batman movie, Logan Lerman would be really good.
Emma Stone as Barbara Gordon/Batgirl
She's a lot of fun to watch on screen, and she can play smart, sexy, and badass like in Zombieland.
Rachel Blanchard as Vicki Vale
She's a natural redhead, sexy, and could pull off a serious reporter with a soft side
Enemies
Jude Law as Two-Face
He is somewhat of a fan favorite for the role, and could portray the character as having two sides and being sociopathic.
Milla Jovovich as Catwoman
Ummm...yeah, no need to explain.
Ewan McGregor as Mad Hatter
Now, some of you may not agree with this choice, but I think Ewan could pull off an excellent Mad Hatter because he could pull the role off similarly to Alex DeLarge in A Clockwork Orange, and could pull off a villain the audience can sympathize with, like the Mad Hatter in the 90's animated series
Michael C. Hall as The Riddler
Perfect for the role. Nuff said.
Rachel McAdams as Harley Quinn
She can portray sensual, bubbly, sinister, childish, and obsessive. All of which are the personality traits of Harley Quinn. Plus, I can picture her doing the phrase "Mr. J"
Vincent Cassel as Black Mask
This one's pretty self-explanatory
Ralph Fiennes as Mr. Freeze
He's good at playing the role of the cold-hearted villain, so I figured I'd go with him.
Gerard Butler as Bane
He could pull off the action like in 300, and the villainous demeanor like in Law Abiding Citizen. Also, he may not be super muscular or Hispanic, but he could pull off a Bane who fights Batman when he uses "Venom", and speak in a Hispanic accent. If he does those, he'd make an excellent Bane.
Rachel Nichols as Poison Ivy
Sexy, great actress, has good range. Need I say more?
Jeremy Renner as Scarecrow
He could do great at switching from a shy professor to a sociopathic and creepy villain.
James Marsters as Man-Bat
He's played monstrous beings in Buffy and Smallville, and he kinda has the built to play Man-Bat's alter ego, Kirk Langstrom.
Sid Haig as Dr. Hugo Strange
Can't think of a better choice. There were some other good choices suggested, but I think Sid Haig is perfect for the role.