Ender's Game by Orson Scott Card
Ender Wiggin is a young boy who is considered to be Earth's hope at defeating the buggers who, years before, had almost destroyed Earth. Children are now to be trained at a young age to determine if they have what it takes to fight the buggers so that once they return to Earth, defeat is guaranteed. The kids are placed in very stressful situations and due to Ender's promise, the teachers alienate him so that he knows he can't depend on friends or teachers to help him out.
I had read this book as a teenager in high school and remember really enjoying it. I vaguely remembered what had happened so the ending wasn't too much of a surprise for me but getting there was still really enjoyable. I sailed through this book because I was so engaged in what Ender was going through.
I don't think it matters too much if you're not a fan of science fiction, I believe you can still enjoy this book. There are science fiction elements but they aren't the primary focus of the story and they don't overshadow the character development.
I'm looking forward to reading the next in the series.
First Line: "I've watched through his eyes, I've listened through his ears, and I tell you he's the one."