ActiveGrid Studio – ActiveGrid Studio enables developers to rapidly build enterprise-level Web 2.0 applications with a minimum of training, time, and effort. Supports Java, PHP, Python. Database supports is the best I’ve seen in an open IDE. Has built in Python and Java environments plus a built in running Apache web server. Highly recommended.
Aptana – Development environment geared towards web development, Ajax style! Autocomplete and assistance for HTML, CSS, Java Script.
Flashdevelop – Actionscript 2 IDE with seamless swfmill and MTASC integration. FlashDevelop is the first alternative opensource IDE to feature AS3 & MXML completion, including Flex2 compiler integration (the best compiler integration after Adobe FB) and AS3 syntax checking. Highly recommended. Requires .Net.
Groovy – Groovy is an agile, dynamic programming language for the Java Virtual Machine. Groovy includes features found in Python, Ruby, and Smalltalk, but uses syntax similar to the Java programming language.
Haste – Haskell TurboEdit – is an IDE for the functional programming language Haskell, written in Haskell.
IronPythonIDE – IronPython IDE is a GUI application written in C#. It is dedicated to the IronPython language which is a .NET implementation of the Python language. It is aimed at providing a nice, easy, full featured development environment for IronPython. Read up on or download IronPython.
IronPythonStudio – IronPython Studio is a free full IDE (Integrated Development Environment) for the Python programming language. It is based on the existing IronPython example that is included in the VS SDK. IronPython Studio is based on the Visual Studio 2008 Shell runtime (royalty free) and can be installed without requiring any version of Visual Studio.
Lazarus – Delphi/Kylix like programming environment using Pascal, compiles to exe and includes gui designer.!
OpenLaszlo – Flash creation, plus much more. Kind of like Macromedia Flex. For everything you need for this visit my Laszlo article.
PyScripter – A very powerful, full featured, professional Python IDE written in Delphi. Highly recommended.
Rec – Decompiler, breaks exe files into C/C++ code.
SPE – If your a Python programmer working on Mac or Windows and your looking for a kick ass IDE Spe is for you! Highly recommended.
Scite – A free source code editor for Win32 and X.
Selenium – Web application test tool. Tests run directly in a browser, including Internet Explorer, Mozilla, and Firefox. Supported platforms Windows, Linux, and Macintosh. Languages include C#, Python, PHP, Ruby, etc.
Sepy – Flash Actionscript IDE. This is really nice! Has class list, auto complete, and compiler. Highly recommended.
SharpDevelop – IDE for C# and VB.NET projects on Microsoft’s .NET platform..
TSWebeditor – HTML/PHP IDE. Has FTP, projects, and css support built in. Very nice! Highly recommended.
Vex – Vex is an editor for XML documents. The “visual” part comes from the fact that Vex hides the raw XML tags from the user, providing instead a wordprocessor-like interface. Because of this, Vex is best suited for “document-style” XML documents such as XHTML and DocBook rather than “data-style” XML documents.