I like graphic novels for a couple reasons:
1. They're a quick read (usually)
2. Comprehension is largely visual, rather than based on words (great for struggling / reluctant readers)
3. They look cool.
(ps. If you don't know what a graphic novel is, basically, its a hard bound comic book)
I recently read three graphic novels (honestly, it probably took me 2 hours total to read all 3, if that). One was a Nancy Drew graphic novel (which I loved---if you are a fan of the original series, this one is set in modern times, but there are a lot of throwback comments that you would appreciate). The second was a Boxcar Children graphic novel (I didn't like that as much as the Nancy Drew, mainly because it jumped around and made me really have to follow the word part of the story close to understand everything). The third was Twilight: The Graphic Novel. Now, I am not a Twi-hard. In fact, it annoys me. However, I did enjoy the graphic novel. It wasn't as full of the teenage angst that I loathe. It would be more appropriate for 5th/6th graders than reading the actual series.
Now, I do have some friends who do not like graphic novels. Because they read like a comic book, you really have to train your brain to read it like that (panel to panel) instead of how we normally read books. But, before you make up your mind about graphic novels, try them out.
(some other great graphic novel series are: The Lunch Lady series by Jarrett Krosoczka, and The Babymouse series by Jennifer and Matt Holm...I know those are both a big hit in my classroom!)