iOS only: Dropbox is a great place to stash your stuff and access it anywhere, including your text files. Nebulous Notes simply creates, edits and saves text files back to your Dropbox account, with some extra security and customisation features, too.
The text files themselves remain simple text, but you can customise how they look on your device with font, size, colour, fixed-width and brightness controls. Because Nebulous Notes also gets a direct link to your Dropbox account and can drop into any folder to read notes, you can also set up a PIN code needed at start-up.
Nebulous does just what it says, but could use two more significant features: landscape editing (unless that's a limitation of a first-generation iPod touch) and a native iPad mode. It's a $1.19 download from the App Store.