The topic for Day 11 is "favorite book genre and what book made you fall in love with it." I've got a couple to mention here.
The Sword of Shannara by Terry Brooks
This is the book that first led me to fall in love with the fantasy genre, way back when I was in middle school. Thanks to Terry Brooks, I've been reading fantasy novels for the last 20 years!
The Hunger Games by Suzanne Collins
I think that a lot of people feel this way about The Hunger Games. While I had read (and loved) several dystopian books before it, this book is the one that really put "dystopian literature" on the map for me. Since then, I've read and enjoyed all kinds of dystopian books (many of which I see as a spin-off of my earlier-established love of fantasy).
Looking for Alaska by John Green
This was the first book that I was assigned to read in my Materials for Youth graduate class. Between the awesomeness of the book, the fantastic class discussion, and the supplemental textbook readings that went along with it, I finally started to see young adult literature as a legitimate reading choice for full-grown adults. I've loved YA lit ever since I was a teenager myself, but after being an English major in college and an English teacher after that, I just felt like reading teen books for fun was something to be ashamed of. No more, though--now they're almost all I read!