In relation to "Going Caseless" thread, I find this article very helpful in categorizing the types of cases for E-Readers:
- Clip case – is a classic one piece snap-on case that is primarily designed to keep your phone safe from bumps, scratches and day to day wear. These are traditionally not made for e-readers or tablets. It’s made from impact-resistant polycarbonate and printed with rich, vibrant, high-gloss graphics from edge-to-edge. All ports for connectors and controls are fully accessible, and it’s thin enough to work with most docks and accessories.
- Hybrid case – this protective, two-piece case sports an impact resistant hard shell and a form-fitting TPU inner liner that protects against impacts and those “accidental” drops. The glossy outer shell is printed with rich, vibrant, high-gloss graphics from edge-to-edge that will safeguard your phone against scratches and also makes it easy to slide in and out of your pocket. Hybrid Cases are sometimes refereed to as the “Best of Both Worlds”, meaning they provide the most protection while remaining as svelte as possible.
- Bumper Case – provides heavy duty double-layer protection for the most demanding users. Its rugged two-piece design consists of a tough, shatter-resistant polycarbonate outer shell wrapped around thick impact-absorbing silicone. Know your e-reader is protected from drops — even on pavement or concrete. The inner silicone liner features hinged dust plugs for the headphone jack and charging ports while the glossy outer shell is scratch resistant.
- Skins – e-Reader skins are fun and decorative ways to add style to your device, while also offering a small amount of protection. They are not the same as cases, which are usually more focused on function and less on style. The skins attach directly to the surface and are easily peeled off for maximum flexibility. You can achieve a more unique look than most cases can manage.
(original article from Goodereader)
I usually go for clip-cases.