Brad Pitt (Inglourious Basterds) as Hal Jordan
I always pictured Hal Jordan as an older, active dude with a bit of grey on his temples and Brad Pitt could definitely give him some character.
Diane Kruger (Inglourious Basterds) as Carol Ferris
She could really sell being the boss of a large air base where she has to constantly bust balls to gain respect.
Harvey Keitel (Reservoir Dogs, Pulp Fiction, Inglourious Basterds) as Krona
Krona should have been the first Green Lantern villain because he's all about uncovering the origins of Oa and imprisoned by Abin Sur. Upon Krona's escape, Abin Sur is fatality injured and crash lands in the Sierra desert. He dies right after passing the ring unto air pilot, Hal Jordan.
Christoph Waltz (Inglourious Basterds) as Sinestro
This was so much fun to think about. I think I mostly want to see Waltz with that ridiculously beautiful mustache.
Kerry Washington (Django Unchained) as Katma Tui
Katma is an intelligent and skilled Green Lantern. Her character would also provide a secondary love interest for Hal, ultimately ruining his relationship with Carol.
Tim Roth (Reservoir Dogs, Pulp Fiction, Four Rooms) as Tomar-Re
Roth is such an awesome and under-rated character actor. His regular speaking voice is perfect for Tomar-Re, along with his build and expressions.
Ving Rhames (Pulp Fiction) as Kilowog
Rhames seems like he would really enjoy playing the older, experienced tough guy. I haven't seen him in that type of role lately and I think he'd be a great fit.
Bruce Willis (Pulp Fiction) as Abin Sur
I'd love to see him in action; how he and Sinestro imprisoned Krona, and his death years later from injuries sustained battling Krona. You get to see his friendship with Abin Sur and is sort of the catalyst to his turn later on.
Samuel L. Jackson (Pulp Fiction, Jackie Brown, Inglourious Basterds) as John Stewart
Hey, a Tarantino movie isn't the same without Samuel L. and would be a bit of a mentor to Hal Jordan later on.
Eric Stoltz (Pulp Fiction) as Hector Hammond
Stoltz plays smarmy really well, and I would love to see him as a comic book villain. He's another under-rated actor.