And me from Sweden
Notepad++ is probably the most popular text editor that is used outside of Notepad. It has a hell of a lot features that make it great for simple or complex tasks. If you just want Notepad with a couple of extra features like line numbers, better search, multi-tabbed interface, spell check, etc, then you can just use Notepad++ out of the box as is.
However, the main features of Notepad++ that make it really useful are syntax highlighting when writing code, syntax folding, multi-editing, aut0-completion, WYSIWYG for printing and lots more. This tool is very popular amongst coders and it supports a whole bunch of languages including C, C++, C#, Objective C, Pascal, HTML, and XML to name just a few. Notepad++ is also actively developed and they release updates fairly often.
Syntax Highlighting and Syntax Folding
User Defined Syntax Highlighting and Folding: screenshot 1, screenshot 2, screenshot 3 and screenshot 4
PCRE (Perl Compatible Regular Expression) Search/Replace
GUI entirely customizable: minimalist, tab with close button, multi-line tab, vertical tab and vertical document list
Auto-completion: Word completion, Function completion and Function parameters hint
Multi-Document (Tab interface)
Zoom in and zoom out
Multi-Language environment supported
Macro recording and playback
Launch with different arguments