Desktop Customization

allSnap
A free system tray program for 32- or 64-bit Windows that makes all top level windows snap to the edge of the screen (or screens) and each other while moving or sizing.
http://ivanheckman.com/allsnap/

Auto Window Manager
Resize programs automatically, adjust transparency of windows, minimize to tray, and stay on top.
http://www.eusing.com/WindowManager/WindowManager.htm

DS Clock
A customizable digital desktop clock that can synchronize a computer's clock with atomic time servers. [Win32]
http://www.dualitysoft.com/dsclock/

Free Launch Bar
Replacement for the standard MS Windows Quick Launch Bar that allows for menus in the quick launch toolbar.
http://www.freelaunchbar.com/

Loop Movie
QuickTime movies that play continuously on the desktop.
http://loopmovie.com/

Samurize
A system monitoring and desktop enhancement engine. [Win 2K+]
http://www.samurize.com/

SeeDesk
A utility which makes the icon text background on Windows 95/98/Me desktop transparent.
http://www.active-dimensions.com/active/software/seedesk.php

SoftProfile
Juggler is a window manager to set any window to be always on top of other windows. Compatible with Windows 95/98 and NT 4/Windows 2000.
http://www.softprofile.com/

Tidy Start Menu
Organizes the Start menu by category. [Win 98+]
http://www.tidystartmenu.com

Transparent Window Manager
A tool to manage windows settings including transparency.
http://www.oreware.com/viewprogram.php?prog=10