If missing the "Show Desktop" icon from your Quicklaunch bar, then one can restore / recover / repair / recreate it again by making a TEXT-file with the following contents:
Save the file as "Show Desktop.scf" and then hold down right mouse button while dragging the file into your Quick Launch bar, and do a Copy/Move here.
Note on WinXP/Vista the task bar can be "Locked" (Right click the task-bar to unlock). The Quick Launch-bar cannot be resized when when "Locked", so items might be hidden when having many items in the Quick Launch-bar.
Note to create your own Send-To "Desktop (create shortcut)", create a new text-file and rename it "Desktop (create shortcut).desklink" (Or copy it from the Send To folder for the Default user).
More Info MS KB190355