My son is seven and he loves, and we encourage, the Great Illustrated Classics. He is reading My Side of the Mountain now. He has read Moby Dick, Three Musketeers, Last of the Mohicans, Swiss Family Robinson, Robinson Crusoe, 20,000 Leagues Under the Sea.... Books like that.
The GIClassics are great. There are a few pictures every few pages or so, and it is classic literature, but it is abridged for younger readers.
He also likes the Magic Treehouse series and Magic School Bus.
***I have read that boys tend to like informational books, so consider getting him a subscription to Zoobooks or another kids magazine! Every month it is a new topic, lots of pictures, but lots of info, too!
Good luck, and great job encouraging Reading!
KATIE