Ultimate Windows Tweaker

WinVistaClub recently released Ultimate Windows Tweaker v 1.1. It is a is a freeware tweak utility for tweaking and optimizing Windows Vista, 32-bit and 64-bit.  It is very powerful and you can tweak over 130 settings. The tweaks are classified under seven categories and can be accessed through a common interface, just like your Windows Vista Control Panel:
1) Personalization,
2) User Accounts & UAC,
3) System & Performance,
4) Security,
5) Internet Explorer (IE7 / IE8)
6) Network Optimization
7) Additional Options

This  utility just a 380 KB. It is an .exe file, and does not require an install.

Homepage: http://www.winvistaclub.com/Ultimate_Windows_Tweaker.html