These are good first set but your son might be past them. They have a big Easy to Build logo on the box (you can't see it on the pictures )
http://www.toysrus.com/product/index...ductId=3780384
http://www.toysrus.com/product/index...ductId=3780364
This is a nice set that has lots of wheels and lots of bricks that can be used for other things.
http://www.toysrus.com/product/index...ductId=2938152
All of these set come with other idea pictures without instructions as well as the instructions to build the item on the front of the box.