The World of John Flanagan
These two series take place in a combination of Medieval and Viking Times. The main characters are orphans and misfits who are taken under the wings of some of the powerful men in their countries. The young men are involved in battles against bullies, strange creatures, invading armies and even pirates! Ranger's Apprentice starts with The Ruins of Gorlan. There are eleven books in this series. After you've read these you may want to read the first book in the spinoff series, The Outcasts.
If you've read these, did you have a favorite character or book?