If weight is a consideration, the lightest of all is the ordinary wi-fi model at 170 grams. The Touch is slightly heavier, 213 grams and the keyboard is heaviest of all 247 grams.
None of them are of "War and Peace" proportions, lol, but Ive got the latter (keyboard) model, and it certainly feels a bit weighty to tote around in my handbag.
Regarding protective cases, the ones Amazon sell are undoubtedly very nice, but quite pricey. If anyone is interested in alternative choices (at half the price,) you might want to take a look at
Mobilefun.uk, or
Duragadget
They both sell cases with a "kick-stand" for Kindle. Very useful if you want to prop-up your e-reader to allow you to be
hands-free whilst taking a coffee-and-bikkie break. (I've got the one from Duragadget. It's an excellent fit and wearing well.)