By far, Lanterns has my interest, since the GL concept as a full on film or series has never been adapted properly by any stretch of the imagination, and I would hope the production focuses on John Stewart and Hal Jordan, with all other Lanterns (any created from the Silver Age-forward) in supporting roles as needed.
After that, the Supergirl project, since SG--like Green Lantern--has never enjoyed a great, creatively satisfying adaptation (Slater's Supergirl was strong in some parts, but the rest of the film was mishandled garbage indicative of that period's approach to DC adaptations). That said, as much potential Sasha Calle had in The Flash, and she's expressed interest in winning the part in the DCU, unfortunately, the fact she was recently in the SG role (it does not matter that it was in an unrelated film universe) is just too soon, and will be to audiences no matter when the SG film is slated for release.
The best option is to cast an unknown, and deliver a forceful SG lacking the often poor writing and whining indecisiveness of the CW TV series' Supergirl.
Lastly, there's The Joker sequel. The first film is one of the strongest comic book adaptations ever set before cameras, but i'm not of the opinion that a sequel was needed beyond WB's need to milk $omething from that great film. Still, it will be interesting to see where the story takes the Joker, and if any other DC A or B-listers (those not used by the DCU) might make a cameo appearance.
