Notepad++ is yet another free opensource tool of great use. As you would have guessed from the name, Notepad++ is a source code editor for most of the famous and command programming languages and a genuine replacement for Notepad in Windows.
Notepad++ is fast and uses less power which is always good for the environment.
Syntax Highlighting and Syntax Folding with support for user defined Syntax highlighting
WYSIWYG support to print your code in colour
Auto-completion, Drag n Drop support, Zoom IN/OUT
Multi-Document and Multi-View with Dynamic position of views
Regular Expression Search/Replace supported
File Status Auto-detection
Multi-Language environment supported
Brace and Indent guideline Highlighting
Macro recording and playback
Have a look at the screenshots here at the project homepage (saved me a lot of time here) which displays the array of features in Notepad++.