This my cast not yours. Keep in mind I can't cast everyone.
Idris Elba as J'onn J'onzzMartian Manhunter.
Known for: RocknRolla (2008), Prometheus (2012) and Pacific Rim (2013).
Reason: I've heard his name pop up for John Stewart, but I'd much rather see him as Martian Manhunter.
Jeffrey Donovan as Bruce Wayne/Batman.
Known for: Hitch (2005), Burn Notice (2007 - 2013) and J. Edgar (2011).
Reason: Michael Fassbender and Karl Urban are too short, Scott Adkins can't act, and Eric Bana sucks. Jeffery Donovan is a great martial artist and unlike Scott Adkins he actually act. After watching darker episodes of Burn Notice I think he'd do an amazing job as both Bruce Wayne and Batman. Not to mention his voice sounds like Kevin Conroy.
Ben Affleck as Bruce Wayne/Batman.
Known for: Jay And Silent Bob Strikes Back (2001), The Town (2010) and Argo (2012).
My Thoughts: Whether you like it or not he's Batman and get over it. Daredevil was a long time ago and wasn't his fault. Just watch The Town and Argo. He might do a great job. Just give the man A GOD DAMN CHANCE!!!!!!!!!!
Henry Cavill as Clark Kent/Superman.
Known for: The Count Of Monte Cristo (2002), Immortals (2011) and Man Of Steel (2013).
Reason: Do I really have to explain. He did a great job and I'm glad he's reprising his role.
Bradley Cooper as Wally West/The Flash.
Known for: Alias (2001 - 2006), Yes Man (2008) and The A-Team (2010).
Reason: He's a really good actor, he can play that cocky chucklehead we all know and love and be serious if asked.
Chris Pine as Hal Jordan/Green Lantern.
Known for: Star Trek (2009), Star Trek: Into Darkness (2013) and Unstoppable (2013).
Reason: A popular candidate for the Flash. After watching Star Trek I'd much rather see him as Hal Jordan.
or if they wanna go with John Stewart.
Michael Jai White as John Stewart/Green Lantern.
Known for: Pandora's Box (2001), Blood And Bone (2009) and Black Dynamite (2009).
Reason: I actually prefer John Stewart over Hal Jordan. White is a solid actor/action star and I think he would do the role justice.
Bridget Regan as Princess Diana/Wonder Woman.
Known for: Sex And The City (2008), Legend Of The Seeker (2008) and The Best And The Brightest (2011).
Reason: Seeing her in action role I think she'd make a great Wonder Woman.
Rhona Mitra as Shayera Hol/Hawkgirl.
Known for: Hollow Man (2001), Shooter (2007) and Underworld Rise: Of The Lycans (2009).
Reason: She would make a stunning Hawkgirl. She's a decent actress and can do great action.
Michael Ironside as Darkseid (CGI) (Voice).
Known for: Total Recall (1990), Superman The Animated Series (1996 - 2000) and Justice League/Justice League Unlimited (2001 - 2006).
Reason: Reason: I would keep Ironside. No one else can do it but him.