Although the DSi isn't available in stores yet, the accessories are already rolling in. Sure there are some cases, some "starter kits" coming with extra accessories, but what about something that actually improves your DSi?
Check out this Dreamgear 3-in-1 Flash Cover— not only does it protect your brand new DSi from scratches and scrapes, but it also covers your outside lens when not in use (to prevent damage), and provides a bright flash for the camera.
This way, you can take pics in a less than well-lit room, and maybe even get a few good shots at night. And really, at $14 dollars, you really can't go wrong here.