It's probably a common suggested, but Harry Potter has been a huge hit, and with good reason. I also picked up the Hunger Games trilogy and finished all 3 books in one week. And as suggested before, try the Hobbit and Lord of the Rings.
A friend of mine has also wrote her own novel, and it's amazing. Look up Personal Demons by Ruthie Hanson.
One of my favorite musicians also has a novel. Look up Adventures of Sha'kona. It's awesome.