Windows 7's "Show Desktop" button (the little rectangle on the lower right corner of screen) is easier for me to use whereas XP's is located somewhere at the right side of Start button. Is it possible to create a "Show Desktop" rectangle for XP similar to the one on Windows 7?
I think this Get Windows 7 “Show Desktop” Taskbar Icon in Windows XP & Vista will contain the facts you want. It works really in my XP machine by using that.
You can make a new toolbar holding only one icon (or more shortcuts and stuff) for the "show desktop" jobby:
Make a new folder somewhere and copy into it the "Show Desktop" from
C:\Documents and Settings\UserName\Application Data\Microsoft\Internet Explorer\Quick Launch.
Right-click on the taskbar and select Toolbars -> New toolbar, then browse and select your folder holding the "Show Desktop".
Right-click on the taskbar and unlock it (if it isn't already unlocked), make sure the new toolbar is in the right place, clear the "show text" and "show title" ticks, make the toolbar as small as possible†, and then relock the taskbar (if required).
† You can make a toolbar a bit smaller than you might think, as after locking the taskbar the little drag-handle disappears, which hence does not need any space. So, try to resize the toolbar to be a few pixels too small to fit the icon, and see if it fits after locking the taskbar.