Hacks Suggestions for a new KSO owner? (Alphonse Mucha Screensavers attached!)

[Nausicaa]

Just got my Kindle SO. I love it.
Did the jailbreak, and a few hacks. I have my own screensavers and use it mostly to read PDFs. I like Alphonse Mucha, so I have his art as my screensavers.

Not sure if there is a preferred format for eBook readers (probably not PDF). Calibre doesn't work very well for me, it crashes a lot. Didn't use the alternative firmwares, I don't really use the internet, but the free 3G was too good to pass up! I don't really use it though.

Looking for suggestions on software you find useful. I think I might get a word processor, any recommendations?

Not sure if anyone recommends hardware either, like some sort of lighted cover or whatever. I don't know which one to get.

Very happy with it, had a Sony reader before, hated that thing, I don't know what I'll do with it besides not use it now that I have a Kindle!

Thanks, I look forward to using this site alot!