Books, I've never read a comic book and have no interest in doing so.
Scott McCloud would like to have a word with you, lol.
This is a stereotypical answer for someone who is "defending" the comic medium, but go read "Understanding Comics", a book that uses an autobiographical visual format to examine, and explain, the medium of sequential visual storytelling. Even if you don't read another comic besides that, it's utterly fascinating on its own merits.
Seriously though, the problem with comics is that even today, the medium is still struggling to find more creators who can take advantage of it. Comics / sequential art offers an experience different from reading words only, different from watching a moving film with audio dialog - it is its own language. A brilliant "comic" story creates a unique experience.
The superhero rags though, still dominate both the shelves and what people think comics are, with translated manga volumes coming up quickly from the rear.
Aside from the obvious Watchmen pick, there's way too much superb literature in the comic medium to dismiss it out of hand; anything that hosts the Sandman cycle can't be all bad. I just finished reading the epic reprint of Scott McCloud's own Zot! that came out last year, and for my money, that was the best "superhero" story I've ever read as a whole, outside of perhaps Watchmen.
I'd like to read more comics but sadly, there is not enough really great stuff to read. (I'm the same way with books; most science fiction and fantasy on the shelves doesn't interest me.)