One editor to rule them all, the NiceEditor (ne):
http://ne.dsi.unimi.it/Like vim, started out on the Amiga, now can run on about anything, and on everything I use. The iMac I'm on right now, the SGI, all linux flavors. The neat thing about it on the Amiga is you can log in over the serial port or telnet in and still have a 'graphical' gui, although character graphics

The only editor I found that I can sit at the SGI and edit remotely on the Amiga while having working drop down menus.
It's inspired by TurboText, which is my number two pick. But ne has undo. I use ne for the things others use vi(m) and emacs for, and I find it a LOT less painful.