Why a case? Gizmodo reports that the Nexus 7's screen does not use Gorilla Glass, so when they dropped their Nexus 7 by accident, the screen broke and stopped responding: [...] (see the "No Like" section)
This case by Supcase looks good and protects the Nexus against minor spills and impact.
Fit is snug so the unit will not slide around, and a piece of Velcro ensures that the unit will not slide out.
All ports and buttons are accessible - camera, microphone, USB, headphone jack, power and volume buttons.
The cover of the case is magnetic which, when closed, tells the unit to turn its display off. The cover can be folded into a small flap in the back of the case, allowing the unit to stand for hands-free viewing - perfect for movies.