Notepad++

Notepad++ is for hardcore programmers who prefer hard coding to IDEs. It comes packed with all the features you could possibly need including code highlighting, support for several language structures as well as custom structures, code formatting, code completion and more. Also, by optimizing its routines, it results in reducing CPU power consumption then reducing the world carbon dioxide emissions. A noble step towards 'cleaner' code itself.

Portable version available on PortableApps.com