My all time favourite text editor is notepad++, which is small, fast and plugin-enabled. Sadly, it's windows only. Following are e few alternatives to notepad++ on Linux. The editors I'll list all have syntax highlighting for multiple languages, are small and fast, tabs for multiple documents and some are even plugin-enabled.
Great syntax highlighting (tons of languages).
Has a side pane for documents.
A fullscreen setting - great for small screens.
Doesn't support projects.
Comes with a nice set of tools (Make RPMs etc).
Built-In CVS support.
Supports overview over functions in left pane.
Does not support projects.
The menus aren't easy to navigate.
This list will grow as I try more editors, so far my favorite is Anjunta IDE, because it's small, clean and supports everything I need - it's like Visual Studio meets Notepad.