I use a silicone cover for my regular kindle 3. Protects (though does attract lint and fine particles) but does not "attach" to it in any way. I am thinking about getting a Fire and I am right now on the page for the Kindle Fire MicroShell Folio Cover by Marware, Graphite... It seems to be a more lightweight cover case, that snaps on the unit with a front screen covering flap that can be used as a stand when flipped in the back (very similar to the popular ipad 2 covers).
On the Amazon site I found and ordered a Multi position leather cover/case which WAS $49.99 and IS NOW available for $4 for Black and $5 for Red Leather. It looks and is described as good quality. Does not have a magnet fastner as my other Kindle, which I think is a good thing.