We are planning on getting DS the Mindstorms for his 9th birthday in a few weeks. He has taken a few classes using the Mindstorm predecessor. He has built and programmed simple machines.

I am looking for input on additional sensors and books with plans to build more things. Quite a few of these books pop up on Amazon when I view the Mindstorms. Are the books worth the $$? Which ones should we get? What additional sensors or accessories should we get?

Also, how do you suggest we store it? Should I plan on plastic totes? I thought that the plastic boxes with sections might be good to keep the parts separated - the type sold in craft stores?

Thank you!