Ra's all the way. Don't misunderstand, Bane and Joker are legitimate threats. But I think that there is no better mirror to Bruce than Ra's. Both want to cleanse the world, and both have made themselves the men capable of doing so. However, with Ra's, you get this man with noble intentions who took it way too far. Don't forget, Ra's is doing it because he wants to fix the world. His methods are awful, but he wants to help.
Plus, it's Liam Neeson. That alone settles this argument.
The choices here are awesome (Batman, Avengers vs. X-Men, and Venom being the main ones I like) but a big one that I think is missing is the current run on The Amazing Spider-Man. It's been a while (To my immediate knowledge) that the Sinister Six have been a real threat, and Dan Slott's run on the title is something I look forward to every issue.
I think that while John Stewart would certainly make an awesome addition to the next Green Lantern movie, I always thought it was a mistake to place Stewart in the Justice League TV show. Before anyone declares me a racist, I'd like to preface by adding I enjoy John's presence in the GL Corps series and his characterization in the aftermath of Rebirth. That being said, Hal (Or Kyle during the late 90's/early 00's) is the primary Lantern, and the one worthy of a film adaptation. Of course, I really hope that eventually the film includes all four Lanterns from Earth.
On the subject of African American superheroes getting film time, I'd love to see The Falcon get an appearance in the next Captain America movie.