I will come back to this conversation later for more details, but if you are not interested in Superman (I am not) I suggest Superman: Red Son.

So Superman: Red Son is basically a re-imagining of if Superman if he were in Communist Russia instead of Kansas. It is a great deconstruction of Superman.

Next suggestion: She-Hulk. At least get your feet wet with

She-Hulk Vol. 1: Single Green Female

I am a huge Daredevil Fan, so I'd be remiss without mentioning Hell's Kitchen's defender.

The Bendis/Maleev/Mack run is pretty epic and creates a great noir atmosphere (See Daredevil by Brian Michael Bendis & Alex Maleev Ultimate Collection for a trade paperback). BUT for an opener I try to suggest Guardian Devil which is a nice closed story line written by Kevin Smith (Clerks, Mallrats, Red State) which gives those unfamiliar an introduction into the Universe. After either of these series, pick up any of the new Daredevils by Waid.

If you want something current: Matt Fraction and Chip Zdarsky's "Sex Criminals" is pretty moving and well written. The covers are often very satirical and fun also.

I specifically didn't suggest some other comic books/graphic novels because I feel like they are suggsted EVERYWHERE. Basically you can read things by Alan Moore, Neil Gaiman, or Frank Miller. Then be covered by most "Must read" lists.

(Editing to add a few more...)

Preacher Kabuki

Persepolis Maus: A Survivor's Tale

There is a great comic with a bunch of stories of scientists, I can't seem to find it right now though, I'll update if I find it.

One thing you SHOULD do: Go to a comic book store, a real comic book store and talk to the people. Let them know what kind of stories you like. If they are not cool, then leave. Most of the time they are VERY accommodating and will WANT to get you involved. If you can't find anything you know you will like, find a locally created comic book and take it home.