Use the keyboard to activate the menu bar

In OSX, is it possible to navigate the menu bar without using the mouse (such as the arrow keys)? I'm looking for something similar to how Windows does this – pressing Alt allows the arrow keys to navigate the menu bar, pressing Enter invokes the menu item. This is more ergonomic as my hands don't have to leave the keyboard to invoke menu items. I'm aware of the various keyboard shortcuts, but unfortunately not all menu items have them.

Followup: I discovered Full Keyboard Access which solves half the problem. With Full Keyboard Access set to All Controls, is there a key that activates the menu bar?

From Mac OSX Keyboard Commands:

Full Keyboard Access (see Chapter 3)

  control+F1

    Toggle Full Keyboard Access on/off

  control+F2 (or control+M)

    Focus keyboard control on menu bar

  control+F3 (or control+D)

    Focus keyboard control on Dock

  control+F4 (or control+W)

    Focus keyboard control on active Window or cycle to next window

  control+F5 (or control+T)

    Focus keyboard control on toolbar

  control+F6 (or control+U)

    Focus keyboard control on palette (utility window)

  control+F7

    In windows and dialogs, switch focus to text boxes/lists/controls

  arrow keys

    Navigate active item

  return, enter, or spacebar

    Select highlighted item

  return or enter

    Select default dialog control (OK, Yes, No, Save, Open, etc.)

  escape

    Cancel action, menu, or dialog

control+F1 to enable Full Keyboard Access (only needed once), then

control+F2 (or control+M) is the command you are looking for.

Note that you can change the shortcut for this in: System Preferences > Keyboard > Keyboard & Text Input > "Move focus to the menu bar"

I highly recommend changing it, the default shortcut is very unfriendly due to the fact that you have to hold down the Fn key to access the "real" F2 key.

My shortcut is Control-Option-Command-RETURN.