I was the happy recipient of a Kindle Touch wifi on Christmas day, so I decided to sew up a case, using Chica and Jo's tutorial as a starting point. My case diverges from theirs in a few ways, being thinner, with elastic straps to secure the kindle rather than a pocket, and velcro as closure.
It took a few tries for me to get it just right- good thing it doesn't require much fabric! The challenging aspect was the straps. One must consider stretch, seam allowances, screen size, etc. I finally got it right- as you can see above, the straps pass the gravity test. The case has been accidentally dropped a few times on a hard floor and the kindle stays put. My first prototype was made with striped quilting cotton. It was cute but had a few functionality flaws. Once I'd made a few decisions re: improvements, I got this faux soft skin silver leather (100% polyurethane). I love my case- it closely securely and cleanly, has a slender profile that fits easily into my bag, and can be comfortably held in one hand while standing and reading on the subway.
Another nice feature is that it will stand up on its own for a comfortable reading position while propped up on a flat surface. The faux leather fabric can easily be wiped clean, which is nice since the Kindle goes most everywhere with me, and I often prop it up on the table while I'm eating lunch. Here's the tutorial, have fun!