One of the most interesting concepts I've seen for tablet covers comes from the Smart Armor iPad 2 Case.
The Smart Armor iPad 2 Case is built with aluminum accent panels, which is definitely practical for its purpose. The magnets will wake up or put the tablet to sleep and effectively protects your device. The additional woven nylon sleeve on the rear end will protect the back of the iPad from any bumps and scratches that may occur from accidental drops. Like many other cases, this one also has cutouts for full access to the buttons and it can be set-up for portrait or landscape viewing for multimedia purposes.
At the moment, the Smart Armor iPad 2 Case can only be purchased if you pledge a certain amount of money. So get to it and give your tablet the proper protection!