My favourite comic books (or "comics" for short, which include everything from strips to graphic novels) currently are Star Wars comics (particularly the legacy of Luke Skywalker eras as well as the conflict that Darth Vader endures while restoring balance to the force), Disney comics (particularly Uncle Scrooge---my favourite creators are Don Rosa, William Van Horn, and Carl Barks), Asterix, Tintin, Lucky Luke, Iznogoud, and Spawn. I consider many of these comic books to be "graphic novels".
I like a lot of the standard Marvel and DC releases like Spider-Man, Fantastic Four, Superman, Batman, i.e., the superhero kind. Even here, my tendencies lean towards epic/cosmic characters such as Adam Warlock, Beyonder, Galactus, Ghost Rider, Silver Surfer, Spectre, and Thanos in sagas such as Infinity Gauntlet/War/Crusade, Secret Wars, and Annihilation.
I further enjoy comic books such as MAD and Archie. Some of the more esoteric discoveries I've enjoyed rading include Bone and Maus. I also grew up to reading comic books like Phantom and Zorro, but I've not been able to read them in years.
I consider comic books to have played a really big role in where I am today, in terms of science, philosophy, and music. I consider comic books to be highly educational, inspirational, and, since I don't have a better to word to describe it, "genius extractors" (i.e., they bring out the best in a person). In fact, a friend of mine just pointed out to me that there's a correlation between "intellectuals" and comic book readers. A lot of the comic books I enjoy portray an amalgamation of characters who could be called "renaissance people". While I enjoy novels and have read many in my time, I consider the graphic novel to be the best form of literature that exists today.
To end on a more negative and whimsical note, the comic book as a form of entertainment is dead. The primary reason I think is just progress. Just like comic books replaced some other form of entertainment for the kids (say the Tom Sawyer/Huck Finn type of adventuring), video games and the Internet are replacing (have replaced) comic books.