Things to watch for in cases
One really important thing to be mindful of when buying a case is how close the case is to the home key popup button.
I have a Speck case I like except for one super annoying problem: the bottom of the holder is right on the edge of the screen so it makes it impossible to press the home popup key. You have to bend down the holder to make room for your finger. Granted the holder part is pretty thick, part of its function is to act as padding between the case and the cover.
Oh, and also make sure you can put the Fire in the case upside down because at least one app I tried doesn't properly rotate the screen so I have to put the Fire in upside down when using the case as a stand. I think a reverse opening case would actually be best but I've yet to see a "manga style" opening case.