I definitely consider graphic novels worth reading, and I think more and more readers have started to realize that in the past 20 years or so. I personally didn't read many comics when I was a kid, but my sophomore year of college a friend forced me to read Watchmen and Batman: Year One and I was hooked for life. My favorite comic authors are Alan Moore, Neil Gaiman, Warren Ellis, and Grant Morrison, though there are plenty of other people who I read. I think the main stumbling block a lot of people have with comics is that "mainstream" comics are the super-hero genre and the genres that people are familiar with from other types of fiction are generally considered to be "alternative" and, with the exception of a handful of fantasy and horror comics, are generally harder to find in (or completely missing from) most comic shops. If I'm trying to convince someone that something is worth reading, I usually try to see what genres the enjoy from other art forms and get them a comic that matches their tastes. So someone who likes Tim Powers novels will get something by Alan Moore, someone who reads urban fantasy will get Fables or Sandman, a fan of relationship dramas gets Strangers in Paradise, the Hunter S. Thompson fan gets Transmetropolitan, etc. That way they can get used to the art form with a genre they already like and branch out into the wider and weirder world of comics from there.