One quick reminder, watch the top screen hinge on the Nintendo DS Lite, usually on the right side it will form a crack.
We just got ours back from being repaired at Nintendo, and this is considered wear and tear damage and you have to pay for it.
I have seen it occur on all colors and pretty much since they were released.
Make sure you register yours with Nintendo so that if you do have to send it back they may give you a break on the cost.
The Nerf Armor seems to be a good idea it has its own hinge to help keep the stress of the Nintendo's hinge.