Eragon is a book that you can read multiple times, and never get bored of. I have read it at least five times, this being my sixth time reading it. I really love the fantasy in this book. Dragons, magic, evil overlord? Checks off on my list. I really love the back-story to the Riders. This book was written when the author was 15, and that really help the way the book was worded. It was more teen-like, it had a certain level of creativity that only teens can achieve.
This book is my favorite fantasy book. I will cover the whole series. I do recommend that you check out The Inheritance Cycle, which is the whole series, on Christopher Paolini's website. I really think that anyone can read this series, and be impressed by the level of writing, and the power in his words.