If you're running Mac OS X 10.9 Mavericks or later, download this version of Stickies which allows you to tuck Stickies windows up under the menu bar.  This is very handy for keeping a notepad available for quick access.

Tip: Hide the window completely

Currently, if you tuck a window up, 1 pixel of the window will be visible just below the menu bar.  If you want to window to completely hide when tucking up, here's how:

  1. Quit Tuck.
  2. Open Terminal.app.
  3. Paste this command, on one line, and press enter:
    defaults write com.irradiatedsoftware.Tuck hideCompletelyTuckingUp -bool YES
  4. Restart Tuck.