I tend to stick to a lot of Vertigo titles as i’m not really big on the archetypal superhero comics, though they can be fun, e.g. Marvel Zombies and the Marvel Civil War volumes (as a side note, i give it 5-10 years and Marvel will be making a movie out of both of these, they’re already converging on the Avengers movie)
I’ve REALLY been enjoying Fables, it’s an incredible story that just keeps getting better! (just finished book 11) the Sandman is also a pretty good series to get your teeth into.
Watchmen is a damn good bit of writing, and reading it makes the movie significantly better. And a couple of more non mainstream comics being Maus and Bone are definately worth a read
oh and if you’re looking for a shorter story with beautiful visuals i can gladly recommend WE3
some of the other suggestions on this page thus far are also definitely worth a good look 🙂