I started reading this book primarily because it's one of the books that I hadn't read before on that list of the "Most Significant SF & Fantasy Books of the Last 50 years". I knew absolutely nothing about the book, and I suppose I wasn't expecting much from it, because I was amazed at how engrossed I became in the story. The premise of the story - that children are taken from their homes and trained at a Battle School to become warriors for the human race - is intriguing, and it's backed up by engaging characters and good, solid writing.
I was really pleasantly surprised by the whole book, so much so that when I finished it, I immediately started in on the sequel, Speaker for the Dead. Speaker for the Dead startled me again in how utterly different it was from Ender's Game - different premise, different planet, even a different age. Again, though, I was roped into the story and found it rather hard to put the book down. And since it ends with something of a cliffhanger, it looks like I'll be reading the next sequel, too.