When it comes to graphic novels, I'm very discerning. I don't buy monthly issues unless I hear rave reviews about the story, and I prefer buying collected anthologies over individual issues.
That said, I really like superhero comics and manga. I'm a big fan of Batman; I grew up in the Iron Age of the 90s and with the , when superheroes were expected to be dark and grim. The Batman of the Animated Series had everything I wanted in a superhero as a kid: he fought bad guys and protected the innocent, but he was intimidating and could instill fright into criminals. In comparison to Superman, Batman seemed more badass and professional, and his lack of superpowers and loss of parents made him more relatable as a character.
My favorite stories are The Dark Knight Returns, Knightfall, Year One, and The Long Halloween/Dark Victory.
As for manga, I really like Full-Metal Alchemist. It's my favorite series, bar none.