We would all be remiss not to mention Hanx Writer, Tom Hanks' typewriter emulator application for iOS.
Strangely, I'd prefer a plain keyboard (w/o a screen) where I could type (for journaling) and have what I type be saved. I suppose this could be easily done with a wireless keyboard connected to my phone. People would think I was crazy, though, seeing me type on a computer keyboard without a computer in view.