I always have a case on mine in order to protect it from cat paws treading on it and cracking the screen. The type of case I use is:
http://www.ebay.co.uk/itm/ULTRA-THIN...item35c2b529a1
I hope the link works.
I bought the brown one because it makes the kindle look like an old book. It also has a lovely lion embossed on the bottom right of the front cover. The front cover is very hard and protective.
I'm not sure if this particular seller still sells them, but I'm sure you can find them elsewhere.