If you want to teach someone a command line editor (that's an if, but at some point it will be useful - at the very least as a backup), then nano or pico (pico is often - maybe always - a symlink to nano) is a good idea.

It would be unpleasant to edit in nano/pico full time (no syntax highlighting or indentation help, etc.), but if you have to do something through ssh and emacs or vim are still too much, they get the job done. What makes them new-user-friendly is that they keep a "menu" of basic commands visible at the bottom of the screen. So you can always see how to save, quit, etc.

For GUI editors, Gedit and Kate were pretty popular for (K)ubuntu and other Debian derivatives.