"A book you didn't think you would like but ended up loving".
The Hunger Games - I avoided this for ages. When I first read the back of the book it sounded like a Battle Royal rip off. And rather bleak and depressing. But eventually I got them on my kindle....and as it turned out, I was blown away. I loved Katniss, I loved the world building, and the fight for survival. It even made me cry in parts. So I'm glad I finally got round to reading it.
Dark Lover (Black Dagger Brotherhood 1). I avoided this like the plague when I started reading urban fantasy four or five years ago. I thought it sounded like sex and vampires and all the characters had stupid names, and if I can't stand the characters' name, I will never read the book. On a boring afternoon at work last year, on a whim I got the first book. And in spite of finding it rather silly, it was totally gripping and addictive, and I loved it. (And went out and got hold of every available book in the series.
Obsidian - one of the first few books I downloaded for kindle, had for ages and never got around to reading it. Turned out to be a real surprise when I did. The Smallville fan in me had a blast reading this book, first of its kind I'd ever seen in YA literature. Alien romance!!! With a main character I wound up loving.
Where The Stars Still Shine- this is not my book. I like my YA books to have some sort of a paranormal element. This book sounds to me like an afternoon movie and if I was at home I probably would have watched with a cup of tea and some chocolate. In a book store, I would never have picked it up. However, I saw lots of reviews posted by some of the bloggers I follow on Twitter, some glowing, some saying it was only okay, and it got to the point where it was like, okay, I have to read this thing. And as it turns out, I'm enjoying it very much.