Glass2k - Small little program that allows Windows 2000/XP users to make any window transparent.
Feewhee - Feel the Wheel (Feewhee) is a tool that Microsoft apparently overlooked while making Windows.
RBTray - Allows almost any program to be minimized to the system tray by right clicking its minimize button.
4t Tray Minimizer - 4t Tray Minimizer Free/Pro - Minimize Outlook, Internet Explorer, Firefox, Chrome and any other applications to the system tray!
DeskPins - DeskPins can be used to make any application topmost, that is, to keep it above all other windows.
DisplayFusion - DisplayFusion will make your multi-monitor life much easier.