Getting into the books is great, especially the trades. You get to buy the entire storyline and read it at once. I quit buying individual books years ago.
I would start with HUSH if you haven't already read it, it's so good. Joker Death of the Family was also really good but its not going to be for everyone. It's a bit dark and quite violent.
A couple others on the MUST list would be Frank Millers Dark Knight Returns and Killing Joke.
If you want to try something totally different and non Super Hero then I highly Recommend Garth Ennis's PREACHERS. It's a fantastic read and moves along nicely. There are six volumes so it is quite long.
And of course there is the Walking Dead, far, FAR better then the TV version.