2. Sinestro
At this present time, Sinestro is one of DC's greatest villains. After many years of taking the sidelines, he's ascended through the ranks. Few other villains are as complex, nuanced, and powerful as he. For comic fans, this is obvious. For noncomic fans, let me quickly summarize Sinestro for you. He was the greatest of the Green Lantern Corp, even training Hal Jordon. However, he felt the Corp was doing an insufficient job defending the universe, so decided to create the Yellow Lantern Corp in response. For years, he was the Corp's nemesis, but recently--last few years--an event happened that changed everything, that made him one of the biggest enemies of the DCU. The Sinestro Corp Wars. Sinestro is powerful, and, like Lex, can attract villains to his ranks of unfathomable powers. Maybe the Sinestro Corp Wars would be too big for a JLA film. Maybe not. either way, there's no harm trying to cram it into one movie, right? ...so who's number one?