What is your reading level? I have read some that would be good for older teens, some for younger kids as well.
If you're a bit more advanced, I'd suggest finding some of Brian Jacques' work. I especially recommend The Angel's Command series. Then there's David Clemet-Davies and his The Sight and Firebringer. I loved those, have you heard of Watership Down?
If you're a bit younger, then Rick Riordan's work is pretty good. I would also recommend the Pokemon manga. It's quite good, actually.