Kingdom Come

This is the ultimate "What If" head-trippy comic featuring "big" names. The premise is simple:
Set twenty years into the future, it deals with a growing conflict between "traditional" superheroes, such as Superman, Wonder Woman, and the Justice League, and a growing population of largely amoral and dangerously irresponsible new vigilantes. Between these two groups is Batman and his assembled team, who attempt to contain the escalating disaster, foil the machinations of Lex Luthor, and prevent a world-ending superhuman war.
--via Wikipedia
The visuals on the book are stunning. Alex Ross, who also co-wrote the story, painted the entire book using models to deliver a realistic, world-weary look to our heroes.