Introduce me to graphic novels?

So far I've only ever read one graphic novel in my life. That was The Sandman: Prelude and Nocturnes by Neil Gaiman(if you haven't read it you can look inside it on Amazon). That was definitely not made for me, way to grotesque. It kind of put me out of wanting to read graphic novels altogether and I know that's not fair to all the other graphic novels out there. That's why I thought I might ask for some assistance; could you guys suggest some graphic novels for me to check out? I feel pretty confident that there has to exist something for me out there as well I just need an eye opener as to what is out there on the market.

I have to add that I found one myself today that I thought looked pretty cool. I found a graphic novel called The Sons of Liberty on Becky's blog Becky's Book Review she makes it sound good, doesn't she?