These are some of my picks for the Justice League and stand alone movies:
Batman/Bruce Wayne – Thomas Jane
He was the Punisher which gives him the dark and gritty acting experience needed for the part.
Superman/Clark Kent – Henry Cavill
He has the part already so no surprise here. He did a great job in Immortals as the lead actor so on that note it should but epic.
Flash/Barry Allen – Nathan Fillion
He was great in Firefly and Serenity. He is an all around great and funny actor. His character should prove to lighten up the group.
Green Lantern/Hal Jordan – Ryan Reynolds
If they pull the Green Lantern movie out of the dirt and get more serious about the story it will work. Here's hoping.
Aquaman/Arthur Curry – Ben Foster
He is a great actor with a good range. I think giving him a chance with this character would prove to be awesome.
Wonder Woman/Diana Troy – Lynn Collins
She has the look need for the Goddess of Truth and she has also shown that she can get dirty when need be. Exactly what you need with this Amazon and she is a great actress.
Martian Manhunter/J'onn J'onzz – Idris Elba
He is an awesome actor and can play from a range of a father to a superhero without to much work. Plus he has that commanding acting status.
These are my pick like me know what you think in the comments below.