just wanted to say that it's also possible to replace the existing font-menu with the standard one which gives the advantage that apple-plus/apple-minus shortcuts work as they do in TextEdit (make selected text bigger/smaller). To do that one has to do the following:
1. open the "MainMenu.nib"-file within the ressources/english.lproj-folder.
2. open/doubleclick on the MainMenu-entry within the "instances"-window (this should open the menubar and makes it possible to edit it. For example, clicking on one entry opens its' sub-entries and hitting "delete" removes a selected menu-entry. This might be a way do declutter menus but I wouldn't recommend it, as it seems (as is shown with the font-resize-function) that if you remove a menu-entry, the shortcut doesn't work anymore, too).
3. Drag the "font"-entry from the Cocoa-menus-palette to the menubar (this should add a second font-menu to the bar)
4. chose the old "font"-entry and hit delete to remove it.
5. save the new bar
It seems that you have to restart Stickies to make the changes work. Probably not the most elegant way to do it, but it's simple and seems to work fine for me. The best thing is that you now can resize the selected text via the usual shortcuts :-)