I absolutely love mine. You can think of it as a low-end ipod... or an ebook reader on steroids. With a fixed amount of 8gb ram, no camera and no mic, you have to decide what features you need. Amazon's Silk is a decent internet browser. The colors are vibrant and the viewing angle extremely good. I've been waiting for years for a Kindle with touch features and a backlit screen.
I enjoy watching movies on it (Netflix), reading ebooks, checking my online projects, and playing games. My wife and I keep a running game of Words with Friends going.
With a bit of work, you can root it and install the Android Market, which really opens up your options.
For me, the one weakness (and this is an odd one) is the version of Kindle installed. It seems to be basically Kindle for Android... which is missing features the dedicated Kindles have, like setting up Collections. I solved that by installing Aldiko. Go Books is also a good alternative.
Sorry this got a bit long, but I'm very enthusiastic about my Fire! It's exactlly what I wanted it to be.