lots of books by Dick King-Smith
Bad Kitty series
The Littles (like the Borrowers, but a long series of books to chew through)
Hank the Cowdog (my DS wasn't thrilled, but if yours likes them, there are LOTS)
Choose Your Own Adventure series
Toys Go Out series

We also keep a lot of magazines in the house:
Muse
Ask
Highlights
National Geographic
Cobblestone

HTH...
DeeDee