1 - Gedit
Gedit is the Gnome text editor for the Gnu/Linux Operating System. It is simple in nature and does not come with many features, but can be turned into anything you wish because of it's free nature and the ability to customize it with addons. Gedit comes with features out of the box that Windows Notepad doesn't have by default, most notably Syntax highlighting for many programming languages. Gedit isn't fit for massive programming projects or handling massive amount of text, but it is perfect for a quick fix to a configuration file or a small edit to a README.
2 - Kate -Kate is an acronym for K advanced text editor. And it is exactly that, advanced. Similar to Gedit it has support for syntax highlighting for many programming languages and can still edit any text file with automatic spell check. Kate has many built in features along with the ability to be modified using addons. The only issue with KATE is that users not used KDE may experience a lot of dependencies along with it. This is a must-have for anyone that has access to it. Hello.
3 - Emacs Electronic MACros
Emacs is probably the most talked about text editor in the programmer/hacker community as it was created by Richard Stallman himself, the original president of the Free software foundation as well as the creator of the GNU Operating System, which is normally paired with the Linux kernel to run what many people simply call "Linux". The text editor is, in my opinion, the absolute best text editor for programming. It is capable of editing text, sending email, playing games, and all while being done by fully changeable keyboard shortcuts as long as 6 keys. This text editor has the option of compiling the project you are currently working on right from it's own dialog. In addition to all of this it can be run in graphics mode and from the command line, whomping VI (in my opinion) as well as KATE and Gedit, however even Emacs has it's limitations.