I have a middle-of-the-road (by the standards of three years ago when I bought it) desktop for all the computer-related things I do, from listening to music to writing to Web surfing. Backups are on both a 1TB external drive and Dropbox.
When I want or need to go portable, I have a NEO. The keyboard's great for writing; the AA batteries last a long, long time; and it does little but word processing. (By which I mean that it has a calculator.) If I want to fart around on the Internet, play games, or keep in touch with people, I have an iPhone for all that.
Oh, and the NEO's rugged, as it was originally designed for kids in school. I've accidentally dropped mine on my floor a few times, with only the odd scuff mark as a consequence. I wouldn't do it on purpose, but I cringe when I think about what would have happened to a netbook in the same situation.