S.T.
I looked extensively at the kindle fire and the nook tablet. For me the kindle was tying you way too much to amazon, it has no cameras and its user interface is horrible. It has almost no storage, yes you can upload to the cloud, but you only have 6GB of onboard storage, so a couple of movies, a few heavy apps and your full up. What I hated most of all was the way it was laid out, everything, yes all apps, books, magazines, everything on your device is laid out in this horrible rotating carousel. So you have to wind and wind and wind this thing around till you see the app you want to open. It wouldn't be so bad I guess if when you tried to stop on an app it suddenly jerks to the next one, opens it, then you have to close it and try again, it is way to sensitive. Also I HATED the lack of outer buttons, if you wanted to turn down your volume, you would have to go to your settings and turn it down onscreen - every time!
It is android, yes, but you can't use the market, and amazon has hardly any apps - I like apps.
I bought the lenovo ideapad (best buy $199) it is the same size, but has volume and hard "home" buttons, 2 cameras, double the storage plus an sd slot - access to android market, flash player, tabbed browsing, I really like it.
I think if you use amazon A LOT you would like it - but I don't like to be made to buy from only one place - my ideapad has a kindle app, and its an excellent ereader.