ToughSkin for iPod nano ($25) and iPod classic ($30) both have the same appeal as ArmorSkin ($30) for iPod nano: they use unusually thick clear or black stiff rubber shells to protect your iPod against light drops and scratches. But whereas ToughSkin is thick on all sides, and squared off on its corners, ArmorSkin is thick everywhere except for its front, which you might assume from the photographs is left entirely open. It?s not: ToughSkin?