So! Jailbreaking... what next?

Hi everyone, I'm new to these forums so please be patient with me. :)

I'm thinking about buying a Paperwhite, and am particularly excited about the ability to jailbreak. I have a jailbroken iPhone, and even though I don't have many tweaks installed, the ones I have are pretty useful, and l like being able to do things with my phone that Apple never allowed or intended.

But what about the Kindles? What do I do once I jailbreak one of those? A quick read of these forums seems to indicate the main reasons for jailbreaking seem to simply be for the KoReader app to read non-native formats, and the ability to set custom screensavers.

Are there any other reasons to jailbreak? I've read through the forums, and I'm not sure about some of the other tweaks and a lot of the information seems to be only applicable to the older Kindles.

So, I was wondering, what tweaks/hacks do you use on your Kindle, and why? What are your favourite tweaks? What would you recommend? What's the most useful for you?

As I say, I'm new here so please be nice, but I'm interested to read what other people think, and their reasons for jailbreaking their Kindles!