I have the Travel Case, which I use when I (wait for it) travel. What fits inside: the Kindle in the M-edge case, the XtraFlex2 light, spare batteries for the light, the charger, the headphones, and my iPod fits in the outside zip pocket. (The USB cable would fit as well, but I leave that home, plugged into my desktop.) I like the way it all zips up securely and then the whole thing (snugly) tucks into my laptop bag.
And then I try not to think about the purchase price of what I'm carrying around in my laptop bag.