I recently bought a full-size bluetooth keyboard with a slot on it for mounting tablets. It's must easier to type on then any portable mini-keyboard and totally worth it if you are going to write a book or code. I consider those little ipad sized keyboards a total waste of time since I started working on one with a full-size keyboard that's even bigger than a laptop keyboard.
I always work with a full PC keyboard, because scientists came up with it, and marketers came up with a small laptop keyboard. I used to just carry it in my backpack all the time. I just have big fingers :)
