I've gotten comfortable with the idea of Cyborg in the League. Maybe I'm just a sheep that can nod in agreement to anything that's put in front of me sometimes, but with the JL the roster is switched around so much that I can't come up with any good arguments for why someone CAN'T be a member.
For that reason, I don't know if Martian Manhunter will be included. I'd like for him to be, but I doubt it will happen since DC seems to be trying to associate him with every team EXCEPT for the main Justice League in the comic books these days. Though I'd love to see the scene from Justice League Volume 2 in the New 52 adapted into the films at some point - the one where the League tried to recruit him for membership and he proceeded to beat the snot out of the big six (the New 52 lineup minus Cyborg). That one panel made the entire volume for me
So, that said, I want the New 52 Justice League lineup for the first movie: Superman, Batman, Wonder Woman, Hal Jordan's Green Lantern, Barry Allen's Flash, Aquaman, and Cyborg.
But if, for some reason, WB remains adamant about excluding Green Lantern (for the 2011 flop) and Flash (since he's got a TV show they don't want to mess with), I would be fine with an alternate lineup.
Superman, Batman, and Wonder Woman are locks obviously. Aquaman should be top priority as well, but I'm not sure how that'll go. Cyborg is probably in. That leaves two open spots that can go to another female character maybe (Element Woman? Rhonda Pineda Atom (to set up for her betrayal)?). Probably not Zatanna or Black Canary since they're in Dark Universe and Arrow respectively.
Spot number seven could go to Hawkman, Ray Palmer's Atom, or maybe a different Green Lantern? John Stewart maybe? I'd doubt that more than Hal, but if it happened, I guess I would be in no position to complain.