Code::Blocks
Code::Blocks is an open source cross platform IDE for Windows, Linux and Mac platforms. Code::Blocks has been designed with the aim to make it highly expendable and configurable. It supports multiple compilers like GCC (MingW / GNU GCC), Microsoft VC++, Digital Mars, Borland C++.
Quanta Plus
Quanta Plus is a popular and feature rich web development environment. It supports both WYSIWYG designing and hand coding.
Aptana
Aptana studio is a feature rich IDE for Web 2.0 development. It is open source, free and is available either as a standalone application or as an Eclipse plug-in. It has useful features like code assist, source control, works with local or remote SQL databases and Ajax libraries.
Anjuta
Anjuta is a Gnome IDE for C and C++. It features project management, syntax highlighting etc. It's advanced but easy to learn user interface is also customizable. It can be extended with Plug-ins and its source editor sports many advanced features.
Bluefish
Bluefish is a code editor for programmers and web designers. It has support for many programming and markup languages. It is lightweight and fast and at the same time can handle multiple documents simultaneously with ease.
TortoiseCVS
TortoiseCVS is an open source CVS tool. TortoiseCVS lets you directly check out modules and perform operations like update or commit just by right clicking on files from within windows explorer. It also lets you perform other tasks such as tagging, merging.
PHPDoc
phpdoc is an open sources auto-documentation tool for PHP. phpdoc can be used from the command line or from a web interface. It can generate customizable output with smarty based templates and output files in various formats like HTML, PDF, CHM.
RadRails
RadRails is a feature rich IDE for Ruby and Ruby on Rails frameworks. It is free and open source and has features like code assist on Ruby and RHTML, integrated server views, supports for debugging and dynamic testing etc. RadRails is available as a plug-in for Aptana Studio.
jEdit
jEdit is a free and open source text editor for programmers. It is cross platform and has features like easy to manage plug-in support, unlimited undo/redo, syntax highlighting for more than 130 file types, various commands for easy source code editing and useful file management features.
KDevelop
KDevelop is a cross platform open source IDE for C/C++ and other programming languages. It has a plug-in based architecture that makes it possible to add new functionality with ease, various project management features and integrated debugger.
