Quis custodiet ipsos custodies?
Creator: Moore, Gibbons
I read the series when it first came out. Reading the collected work doesn't really match the anticipation people felt waiting each month (and sometimes longer) for each new issue to come out. I'd just started woring, and so had plenty of money to spend on things like comics, and the mid eighties was a great time to rediscover the genre.
Watchmen was unique, and in many ways it still is. It didn't look like any other comic at the time. The covers had a single vivid image which was actually the first panel of the story, but which also seemed to encapsulate the main theme of the issue. Each issue had extra material after the story - excerpts from the autobiography of a minor character, a biography of a comic writer, a psychiatrist's note on his pychopathic patient - which weren't necessary to follow the story, but which added to the texture of the story. And there were no ads at all. Everything about the comic was different.
It's also a completely self-contained story. It isn't a 'special edition' of an existing story, and there have never been any sequels. It contains its own backstory and feels like the culmination of a much larger work. It's just astonishing.
"The longest sustained narrative in the English language"
Not British, or Science Fiction, Cerebus is a remarkable achievement. Sometimes uneven, and these days almost shunned by the comics fraternity, it remained the only regular comic I kept buying from the days when Watchmen came out.