I just finished listening to Extremely Loud and Incredibly Close on CD. I wish the main character, a nine-year-old named Oskar Schell, lived in my neighborhood. He's smarter than his years, but isn't a smart-mouth showoff. He plays the tambourine, is an inventor and spends the book looking for the lock that fits a key he found in his father's closet. (His father died on 9/11.) The flashbacks by the grandparents didn't add too much to the story for me. I wanted to read more about Oskar and his experiences. He's a character you keep thinking about long after the story is done.
The book's author, Jonathan Safran Foer, also wrote Everything Is Illuminated.I'm listening to that now on CD. It's quite intriguing and at the beginning, especially, it is hilarious -- particularly the narrator, a Ukrainian named Alex. There are flashbacks as in Extremely Loud but in this book they are more helpful. The main character, or "the Hero" as Alex refers to him, is in the Ukraine to find the woman who saved his grandfather from the Nazis. The story unfolds slowly and it breaks your heart.