Ah, the graphic novels vs. comics debate. Let me weigh in as both a public librarian and comics reader:
"Graphic novel" is a marketing term publishers use to convince libraries and bookstores to stock comic books, or to convince sensitive or pretentious readers that they are not children or social outcasts for liking comic books. Over ten years ago, most of my older colleagues wouldn't have dreamed of stocking comics in the library, but call them "graphic novels" and give them an actual spine, and things change.
I know Wil Eisner meant something else by the term when he coined it, and some of his works are as close to be actual novels as any comic book could be, but that's not how it's usually used today. When I see the term "graphic novel" applied to works of non-fiction like Maus, Persepolis, other memoirs, comics journalism like Joe Sacco and Ted Rall's work, Larry Gonick's History of the World, or comic biographies, it makes me cringe.
Then you get those who say that something like Watchmen or your typical trade paperback can't be a graphic novel because it was originally released serially in separate parts. Well, so were most of Charles Dickens' novels, and some consider him the greatest novelist in the English language.
Anyway, I'm a huge Warren Ellis fan, and especially recommend Transmetropolitan, Planetary, Orbiter. The Winter Men is another interesting title I've read recently.
