Comment I rooted my Kindle Fire a few days ago (Score 3, Interesting) 103
The instructions were brand new and horribly incomplete at the time, but it was fun to hunt down all of the pieces to the puzzle on an environment I was completely unfamilar with. I was mostly interested in learning more about the Android platform, and also to enable Google's Android Marketplace and other Google apps.
I unrooted the Fire (so that Amazon Video on Demand would continue to work), and used the Marketplace to download a better video player app (MX Video Player) and a number of decent games. I didn't go with the Dolphin browser or the GO Launcher for my defaults. (Not that I'm excited about Amazon's launcher.) So basically, I have what acts like a stock Kindle Fire, except I've got Android Marketplace access. I think that combination makes this a winning device. I'll still purchase from Amazon when it makes sense, but I'll go to Google for selection.
The only significant snag I've seen so far is that the pop-up menu bar onto the Kindle Fire slightly confuses apps by a number of pixels about screen size or placement. Some apps will chop off the top of their app's display. Of course, others will use the bottom of the screen for their own menu bar, leaving you with scant pixels (in landscape mode) to hit their buttons. That, and a few apps like the VLC Direct player seems to get me into situations which lock my Kindle from time to time, so I mostly don't use it.
At least when I download Marketplace apps, I can delete applications now and now worry about them haunting my 'cloud applications' screen forever. If I download Angry Birds Free, and then pay for Angry Birds (and remove the free version), do I really need to see two different Angry Birds icons on my device forever, Amazon? Well, I asked, and you apologized that I couldn't delete it. You hinted that you may allow this in the future, and you gave me a $5 credit for my inconvenience. You're not so bad.
Anyhow, rooting and installing the Amazon Marketplace is a little bit of a bumpy road, but it seems to be totally worth it.