I'd say worry less about a particular universe, and look for particular writers and artists who you gravitate towards. Here are a couple great writers and some of their best works:
Alan Moore (if you like dense, intellectual, heavy, and frequently darker stories)
Batman: The Killing Joke
V for Vendetta
Watchmen
Swamp Thing
Frank Miller (dark, sharp artwork with good story)
Batman: The Dark Knight Returns
Sin City
Mike Mingnola (bold, asymetric art with mythological stories)
Hellboy
Neil Gaiman (clever, grand, quirky stories)
Sandman
Other great series worth getting into:
Bone
Y, the Last Man
Bone and Watchmen are both some of my all-time favorite works of literature, and I was an English major.
Bone is in my top-5 favorite books, along with Good Omens, The Hobbit, 20,000 Leagues Under the Sea, and Stranger in a Strange Land. It is one of the finest works of epic literature since Lord of the Rings. It is elegantly simple like a really good Pixar film or a Looney Toons cartoon, where it makes is so humorous and whimsical that you don't realize until you're fully engaged how deep, nuanced, and serious the full story is. You could share it with an elementary school student (although Empire Strikes Back levels of PG violence will lead to discussions with younger children), and both thoroughly enjoy it. The pacing and depth is perfect, where it starts lighthearted and slowly gets heavier, more complicated, darker, and more serious... but with the weight always relieved at just the right time.
Watchmen is one of the most brilliant works of literature I've ever read. I was an English major and usually end up spoiling the endings of stories for other people, because things are usually predictable. Watchmen managed to have an original ending that I was not able to predict. It managed to actually get under my skin. It is seriously dense to the point of requiring a second read to realize everything you missed (like, understanding WTF is up with the "Tales of the Black Freighter"), and it is VERY adult. It is a very meta comic, questioning and being critical of super heroes and of cold war politics.