While many know that OS X allows keyboard navigation of menus via the keyboard, i.e. typing a letter will jump to the first command that begins with that letter, you can also jump to the bottom or top of the menu by typing Option-Down Arrow or Option Up Arrow.
What may not be generally known is that this also works in pop-up lists almost everywhere, such as pop-up lists in webpages, font menu pop-ups, various Filemaker pop-ups, Contextual Menu pop-ups, etc., etc.
Mac OS X Hints
http://hints.macworld.com/article.php?story=20040107143524900