Notepad ++

Features

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
Document Map
Auto-completion: Word completion, Function completion and Function parameters hint
Multi-Document (Tab interface)
Multi-View
WYSIWYG (Printing)
Zoom in and zoom out
Multi-Language environment supported
Bookmark
Macro recording and playback
Launch with different arguments