Well, the absolute BEST non-classical book series is, of course, The Adventures of Tintin.
I also enjoy Sharon Creech's books. Namely Replay, Ruby Holler, and Bloomability.
And "The Enchanted Castle" by E. Nesbit.
And "Journey to the River Sea" by Eva Ibbotson.
And (this could go on for awhile...) Inkheart by Cornelia Funke (although the sequels aren't all that great in my opinion).
And Watership Down by Richard Adams.
And there you have it! Some of my favorite books that aren't classics.
Live long and prosper!