The source code editors are required by the developers to code with ease. There are n number of sophisticate, useful and powerful text editors available as freeware, shareware and on trial basis. Even though there are IDEs and GUI editors available to provide WYSIWYG interface for designing and development, the traditional text editors with advanced features score over the GUI editors in providing lightweight solution for development and debugging process. Here are some of the most useful and powerful source code editors, each having an edge over other.

Edit Plus: Edit plus is rightly said the internet-ready text editor. EditPlus comes in handy for web developers not only coding with ease (through syntax highlighting, URL highlighting and auto completion), it also provides FTP support which enables the developers to transfer the files through EditPlus. It is a powerful text editor which serves as HTML editor, PHP editor, Java editor and Hex viewer for Windows. By default it supports syntax highlighting and auto-completion for HTML, Java, PHP, CSS, C / C++, ASP, Perl, Javascript; while the support for other programming languages can be extended through custom syntax files.
Notepad++: Notepad++ is a free source code editor for Windows. It is an effective replacement for Notepad and helps the developer to debug the code with ease. It is a simple code editor, without any bells and whistles as Edit Plus, but is a good start for beginners. Some of the features offered by Notepad++ are line number ruler, powerful search and replace mechanism, multiple redo / undo, code indentation (and nesting), etc.
Komodo Edit: Komodo Edit is a free and open source code editor for all the major platforms. It is supported by Windows, Mac, Linux and provides auto-complete and code intelligence feature for almost all the programming languages — PHP, XML, HTML 5, CSS 3, Perl, Javascript and so on. This highly sophisticate text editor also provides the flexibility of remote file editing and integrates the toolbox for macros, code snippets and shell commands. Apart from the basic functionality provided by the editor, it offers various extensions and plugins to highly customize and extend the capability of the text editor.
Bluefish Editor: Bluefish is an open source code editor (released under GNU GPL license) designed for web developers and programmers. Apart from the basic features provided by all the source code editors, Bluefish provides some outstanding features like multi-threaded support for remote files using GVFS, upload / download synchronization and integration of external programs (like javac) to handle advanced text processing or error detection. It is available as free download for all the platforms.
Caditor: Caditor is a very basic source code editor available for Windows. This simple to use text editor provides the basic functions and features of syntax highlighting and auto-completion along with the some advanced features namely, FTP support, compiler integration, encoding conversion and plugin system (for extending the capabilities of the editor).
Source Insight: Source Insight, as the name suggests, helps the programmers and developers not only to code the programs, it comes in handy for understanding and analyzing the code as well. Source Insight is designed for large, demanding, real world programming projects and thus provides the features as required by the enterprise-level developers. Apart from parsing the code, Source Insight also displays reference trees, class inheritance diagrams and call trees which make it easier for the developers to assess the progress and debug the projects with ease.
TextMate: TextMate is a dedicated text editor for Mac users. This easy to use and elegant text editor is designed for providing lightweight solution to the code-editors which “just works”. Even though TextMate is not an IDE, but its features of powerful snippets, macros, and unique scoping system, provides features that even a language specific IDE lacks.
UltraEdit: UltraEdit is an ideal editor for editing text as well as the source code in languages like XML, HTML, PHP, Java, Javascript and Perl. UltraEdit provides various packages for Windows, Linux and Mac users. It offers 30 days free trial package and is available in three distinct flavors varying in features depending on the level of proficiency of the programmer.
ConTEXT: ConTEXT is a small, fast and powerful freeware text editor, developed to serve as a secondary tool for software developers. It is available in two versions; the desktop version and the portable version. Most of the editors are basically best used as a desktop application, but the portable version of ConTEXT makes it readily available for use through USB stick.
TextWrangler: TextWrangler is the text editor designed specifically for Mac OS X. Its features and functions range from that of a general text editor to programmer’s text editor and serves as Unix and server administrator’s toolkit. It is a simple yet powerful text editor which allows you to configure the system files and help you in coding programming and mark-up languages.

Which one fits you best?