Tech Tool Store - Tech tool store is an IT professional application which contains more than 600 free technician tools packed in a simple, fully featured interface.
NTLite - The Ultimate Windows Customization Tool
Tron Script - Tron is a glorified collection of batch files that automate the process of cleaning up Windows systems.
Win Toolkit - BUGS: Do not post bugs in the comments.
Autoruns - See what programs are configured to startup automatically when your system boots and you login.
Ultimate Windows Tweaker - Ultimate Windows Tweaker is a freeware Tweak UI Utility for tweaking and optimizing Windows.