I know it's not super popular with fans of the source material but I loved Watchmen (2009), specifically the director's cut. It's probably my favorite standalone superhero movie.
The theatrical cut left out some (what I believe to be) important scenes that expanded on character backgrounds and motives. The ultimate cut is nearly identical to the Director's cut from what I recall, but also includes animated segments depicting 'The Legend of the Black Freighter" that appeared in the graphic novel and bloated the runtime to 3.5 hours which is just insane. So between the three versions, the director's cut feels like it does the best job of telling the story without overstaying its welcome.