When considering a Kindle I borrowed a K2 from a friend. He had the "official" Amazon case (which appears to be retired and has been replaced with this one which adds a retaining strap
http://amzn.com/B002Y27P6O ). The case added a bit of weight but it was still easily handhold-able. I really liked the book motif it imparted.
However, I ended up getting the DX and didn't want all of the additional weight on a device that was already heavier. I chose the Octovo sleeve (
http://amzn.com/B002KQ115A ) and have absolutely loved it. No regrets.