Oberron covers are really expensive, but as far as I know they're pretty decent for protection. What you may want to consider is one of the silicone covers that just fit over it like a sleeve. You can slip them on and off easily. B/N has a bunch, I have the graphite one now.
Before, I was using the Alice cover up until I started getting autographs on that cover
Now the cover sits on my shelf and the silicone sits on the nook.