Ok, so I've had the fire for a couple of weeks, and have enjoyed using it. I also have had the opportunity to review a few cases, and figured I would share my thoughts.
As with any tablet, protection is important. I wouldn't think of carrying my Fire without a case any more than I would my iPad or iPhone.
Marware - Microshell
The Microshell from Marware comes first. I really like the way it fully surronds the tablet, providing a non-slip surface on the out side, and combines a great east to fold back cover. This makes reading it like a book quite easy, and provides decent scratch protection for the entire unit quite nicely. I have my doubts that it would provide much as far as impact protection, but I don't really plan on treating it too rough any way.
Marware - C.E.O. Hybrid
Marware's C.E.O. Hybrid is a beautiful case. Nice leather grain, with just a touch of padding makes it feel much more likely to provide impact resitance should I lose my grip on the Fire. It has a nice hand strap for easy one-handed holding of the Kindle Fire, and a strap that holds the cover tight to the screen when closed. It provides coverage to the corners, but very little to the edges, making it much more of an executive and responsible adults type of case.
Belkin - Verve Tab Folio for Kindle Fire
Belkin's case is pure simple utility. Not a lot of bells or whistles, not much to protect your investment. The magnetic closure on the strap is a nice touch, but there are far better cases (like those above) available at the same price point.