Hard one. Had a lot of comics that I loved from 2013.
What Scott Snyder has been doing with Zero Year has been amazing and it has become one of my all-time favorite Batman stories to date. Issue #24 was an amazing reintroduction of Bruce Wayne as Batman for the first time in the DCnU, as well as an epic origin story for The Joker! This issue by far is my favorite of 2013.
@waezi2: In terms of single issues, I'd go with Thor: God of Thunder #11 and #12, Teenage Mutant Ninja Turtles: Secret History of the Foot Clan #3, Infinity #3, Batman and Robin #18, New Avengers #9, New Avengers #10, New Avengers #12, Avengers #13,Indestructible Hulk #9, and Origin II #1. For a whole series, I'd have to go with Brian Michael Bendis' Daredevil.