On the case front I got a cheapie neoprene one off ebay.
My Kindle (an old one now with a keyboard) -I don't think they do them any more), after coming back from Spain my screen no longer worked, there was some internet chatter at the time that the airport scanners were destroying Kindles.
Amazon were very slick replacing it and not had any problems since, was advised to place it on top clearly visible so they don't need to turn up the scanner to identify it.
I don't know if this is an urban myth, but its worked so far.