NTLite - The Ultimate Windows Customization Tool
Win Toolkit - BUGS: Do not post bugs in the comments.
Dism++ - Dism++ is a free portable Windows optimizer and manager.
Winbuilder - "WinBuilder is an engine designed to build and customize boot disks (Live CDs) based on...
WinReducer - Customize Windows (Integrate cursors, themes, wallpapers or change files to improve Windows...
Windows AIK - The Windows® Automated Installation Toolkit (AIK) is a collection of tools and documentation...