I've started indulging in a life long fantasy of writing and in my writing I've found it almost impossible to write on a (standard) computer. They have FAR too many distractions, even the option of being able to change you font size for me is a distraction ("oh, would it be easier to read on this screen in size 11, no, size 10 it is..."). To have something that you just sit at and fire your thoughts onto, complete with spelling mistakes, missing punctuation and shit sentences and paragraphs, is really liberating. It's what I was wanting to do all along, I didn't want to check spelling, I wanted to tell a story.
When writing I now use a Tandy WP-2 word processor, or "Electronic typewriter" as it's 1989 marketing called it. It cost me £12 (US£20). It's got a daylight reflective 8 by 80 character screen, runs for more than 24 hours on 4xAA batteries and stores around 70 pages with the 128Kb memory upgrade I got it. With it's 5Mhz Z80 processor all you can do with it is type. It works brilliantly, it's so slow that it actually cant insert text at the rate I can type. It drives me to write more and then only when the creative part is done, so it never interrupts, comes the boring part of the editing and spell checking on a full computer.
Before I remembered about the existence of devices like the WP-2 I was quite tempted by the idea of a type writer, with a scanner and OCR software it's not even hard to upload your work to a computer for editing. However on portability alone the A4 sized WP-2 wins, but just encase, I do own an Olivetti as well...