Percy Jackson books are aimed at boys? Please don't tell that to my 9-year-daughter, who thinks they are the best books EVER! I liked them, too, though not nearly as much as I liked the Harry Potter series.
I read a lot of books that are recommended to me by my kids. I like a lot of books that are aimed at older elementary school kids and tweens. Books for adults often have too many extremely disturbing scenes of violence. Some of my favorite books that are aimed at kids are:
the Books of Ember series- Jeanne DuPrau
Olive's Ocean- Kevin Henkes
Elsewhere- Gabrielle Zevin
Memoirs of a Teenage Amnesiac- Gabrielle Zevin
If I Stay- Gayle Forman