Have you ever used one of the Notepad ebooks on the Kindle? If not, you can make one by creating an empty ebook and then adding typed notes. They never really worked well for me, which is why I'm glad to finally get a real notepad app.
Late last night the latest app from 7 Dragons went live in the Kindle Store. Notepad brings most of the features of the standard Notepad app to your Kindle. You can read and edit TXT files, and it has 6 font sizes and 2 font types for you to choose from.
I managed to get in on the beta testing, and the app was pretty good then. Now it's better. I like how the shortcuts are designed, and I like the design of the menu system. It's also pretty fast at showing what you type. Also, speaking as someone who has an original Kindle, it was a joy to see the cursor move around the screen so quickly.