Green Lantern Corp all the way. John up front and center, plus numerous supporting cast (no Hal). Go for big action, go for high stakes, make the danger a galaxy wide threat, and punch home that there's more to it than Earth in the DC movieverse.

I want to see a galaxy explored. I'm sick of Earth. I want my Tatooine and Coruscant in a DC version; I want to see the Corp fighting a huge intergalactic threat, one that affects more than just Earth (heck, even keep it away from Earth entirely, have the threat elsewhere in the universe). I don't see why a humanoid galaxy can't replace Earth and the human population for emotional connection and concern. By having John as the lead (and Guy), you already have that connection, so I say go for broke and just nix Earth entirely and show that expanded universe beyond our own little round pond.