Most people don't give a text editor a second thought, flame wars have been fought over other editors. Here are a few thoughts on a small handful of the plethora of editors out there on various operating systems.
A fun little editor ported from Plan 9 that is easily expandable. You might be able to find Wily a work-alike in your distros' repos. It is my favorite editor at the moment.
Here's a page that talks about acme a bit more.
An MS-DOS program that appears to have been loosely based on Unix's ed . When you were using MS-DOS 2.11, you made do. You can program with it, don't, it's a line editor. The source code is available online.
I understand this was a good editor for VMS. It made heavy use of the extended keypad on the terminals. Suffice it to say that I preferred mail's text editor at the time. I found learning vi more user friendly. It can be found online.
Emacs is great programming environment. It has something for everyone, and probably is close to an operating system. It's available on most systems and has spawned a handful of versions. It can be used in a text terminal or on a GUI. You'll find Gnu Emacs available on most modern systems. It was my favorite for several years.
(Yes, XEmacs can be run in terminal mode, if you want to go to the trouble of installing it. It may not be available in your repos.)
SciTE is Scintilla based Text Editor. It has a lot of features, including syntax highlighting for a number of programming languages, and is easily configurable.
TextEdit from NextStep made it's way into OS X as the primary text editor. The GNUStep version has a few bugs that prevent its use as a primary editor, like file names must end in ".txt".
Descending from Unix's ed/ex, it's inspired vim, neovim and countless others. Vi/Vim were once found on nearly all Unix-like systems. If Vi/Vim aren't installed by default, you can almost definitely install them from your package manager.