Watchmen, it's a book by Alan Moore, with artwork by Dave Gibbons, it really is rather good.
If you are going to see the film and you have not read the book, THEN YOU'RE DOING IT WRONG.
I'm only saying this because sometimes people go and see films and then they get the wrong idea about the book because the film's director changed something, for example, did you know that Tolkien NEVER WROTE A SINGLE DWARF JOKE AND I'M STILL QUITE ANNOYED THAT PETER JACKSON DID THE WHOLE DWARF THROWING GAG.
And there were no Elves at Helm's Deep.
I havn't seen it yet, but if you come out from seeing Watchmen and you liked the happy ending, then you know that Zack Snyder has done it all wrong.