K.C.
There is a toy called Motor Works that is absolutely perfect for boys this age! It comes with a car, a motorcycle and an airplane that you can put together and take apart with the included battery-powered screwdriver. I have seen it sold through Discovery Toys and also through DT on Amazon. I know that you can also get it Lakeshore Learning, but I think it may have a different name. http://www.amazon.com/Discovery-Toys-2288-Motor-Works/dp/...
If you get it through Discovery Toys directly, it comes with a carrying case, a manual screwdriver and - most importantly - a lifetime warranty. The other options don't offer those extras.
Otherwise, my son loved his toy garage for hot wheels at that age. He also started playing a lot of board games.