Notepad - Most simple text editor. Just plain text, saves in .txt format.
Microsoft Visual Studio - Microsoft Visual Studio is an integrated development environment (IDE) from Microsoft.
Notepad++ - A free source code editor which supports several programming languages running under the MS Windows environment.
IntelliJ IDEA - Capable and Ergonomic IDE for JVM
Notepad3 - Notepad3 is a fast and light-weight Scintilla-based text editor with syntax highlighting.
Xcode - Xcode is Apple’s powerful integrated development environment for creating great apps for Mac, iPhone, and iPad. Xcode 4 includes the Xcode IDE, instruments, iOS Simulator, and the latest Mac OS X and iOS SDKs.