Always On Top Maker : 
Always On Top Maker is a tiny interface less tool to make any window "always on top", or, make a topmost windows not always on top. How to use: Run AlwaysOnTopMaker.exe, then you can use 2 hot-keys, one is CTRL-ALT-T, is to switch the foreground application "always on top"/"not always on top", the other hotkey is CTRL-ALT-Q, is to exit Always On Top Maker.
Always On Top Maker Memory Use test: 376K (XP 32-bit) | 1584K (Vista 64-bit) | 1068K (Windows 7 64-bit)
Always On Top Maker File Size: 5.9KB and runs on XP Vista Windows 7
Always On Top Maker Website
Download Free Always On Top Maker 1.0
TurboTop Windows Always On Top Tool: 
Turbo Top : TurboTop is a little tool which will sit in the systray. By clicking on the TurboTop icon, you'll be presented with a menu that displays all windows that are currently visible. Simply click on the menu item that corresponds to the window you want to make "Always on Top." The popup menu also shows which windows are currently "Always on Top" by displaying a check mark next to the name of the window. When you click on a checked menu item, TurboTop will make that window not "Always on Top."
TurboTop Memory Use test: 3140K (XP 32-bit)
TurboTop File Size: 438KB and runs on XP Vista Windows 7
TurboTop Website
Download Free TurboTop 2.7
Power Menu Windows Always On Top Tool : 
Power Menu is a small application that adds more useful options like "Always On Top", "Minimize To Tray", "Priority" and "Transparency" sub menus to all top level system menus
PowerMenu Memory Use test: 2284K (XP 32-bit)
PowerMenu File Size: 109 KB runs on All Windows
PowerMenu 1.5.1 Website
Download Free PowerMenu 1.5.1
xNeat Windows Manager: 
xNeat is a very handy Windows utility that gives full control over your windows and adds functionality including Always on top, Send to tray, Taskbar shuffle, Windows Transparency , Hide Windows and much more.
xNeat Windows Manager Lite Memory Use test: 468K (XP 32-bit)
xNeat Windows Manager Lite File Size: 828KB runs on All Windows
xNeat Windows Manager Lite Website
Download Free xNeat Windows Manager Lite 3.0.0.1
DeskPins Always On Top Tool: 
DeskPins can be used to make any window topmost, that is, to keep it above all other windows. Just grab a pin from the DeskPins icon in the system notification area and click on any window. This functionality is identical to the "Always on Top" setting found in some programs. With DeskPins you can add this feature to any program!
DeskPins Memory Use test: 2568K (XP 32-bit)
DeskPins 1.30 File Size: 95 KB and runs on All Windows
DeskPins 1.30 Website
Download Free DeskPins 1.30
FileBox eXtender Stay Always On Top:
FileBox eXtender adds Always On Top, Recent and Favorite List option in a "push-pin" button to all of your "top level" windows that enhances windows usability powerful ways. The Always On Top function prevents any window you "pin" to the desktop from being covered by any other windows.
FileBox eXtender Memory Use test: 12564K (XP 32-bit)
FileBox eXtender File Size: 1.5 MB and runs on All Windows
FileBox eXtender 2.00.03 Website
Download Free FileBox eXtender 2.00.04 32-bit | FileBox eXtender 2.00.04 64-bit
Always On Top Tools Related Software:
Hide Folder in Windows XP Vista 64-bit
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Folder Marker : Mark Special Folder
Windows Search Replacement
XNeat Windows Manager
Restore Desktop Icons