What is the best Kindle 2 case available?

It really depends on your needs. As far as folding cases, the m-edge line are excellent. If you want a bulkier one with a strap to keep it closed, the m-edge prestige is nice. It has a little pocket in front as well as room for a book light.

If you want something less bulky, the m-edge go eschews the book light storage, pocket, and strap while still providing good protection. This is the one I went with, and it's quite nice.

The Kindle Sleeve Case from SF Bags - not to be confused with the slip case mentioned above - gets my vote. Great fit, good protection for the Kindle2, and SF are always great to deal with. I've used their Cargo messenger bag and the laptop slipcases for the last few years and they easily take the punishment meted out by regular long haul travel.

@M. Alade, agreed indeed. Here is a link:

http://shop.hardgraft.com/category/e-reader-cases

Its beautifully hand-crafted stuff with immense attention to detail.

If you're going for the sophisticated, "I want my kindle to look like a book" look, and you're willing to shell out a bit, I'd go for This Cole Han Case

Or, if you want the more utilitarian, techy, "this is another piece in my every-growing electronic arsenal" image, here's a case that looks a lot like those ubiquitous Macbook neoprene sleeves, but a little more unique.