Program: Sublime Text v2 or 3 (beta)
License: Free to Try, Per-user license or Commercial (currently no enforced time limit, no disabled features)
Description: Sublime Text is a text editor for developing code, using color schemes, highlights, and auto-tabbing/spacing. Sublime Text allows open-source plugins using a package manager to enhance the user experience as well as expand the tools and commands available. While the program is cross-platform, only the Windows release offers a portable version.
Website: http://www.sublimetext.com/
Other: They already provide a portable version for Windows 32/64-bit