Personally, I think the best thing about the n8x0 series is that it's running on a real Linux system. Plenty of devices out there let you go on the internet and check your email, but if you're looking for a pocket size computer that gives you the freedom and power of an open source linux OS under the hood, the selection gets much more narrow. This allows me to, for example, install BASH and do some scripting to help me out with administrating other computers. Also, I think the open platform gives developers a lot more options on how they would like to go about building applications for the system. My porting attempts so far to the device have been a pretty good experience. Seems to me if you're not using the n8x0 for its linux features, you're missing out on a lot of the value of owning the device.

Other than geeky linux stuff and computer admin tasks, I use mine for taking notes in class, word processing (google docs), keeping up with news (google reader), playing music/video (both on the device and controlling other players remotely), playing games, reading ebooks, and much more.

One of the most useful things about the device that I've found is how long the battery lasts even if it's connected to a wireless network all day. Since I have access most places I go, including all over my campus and where I work, my friends and co-workers can send a message directly to me no matter what I'm doing and I can respond in the time it takes to take it out of my pocket.