There are times that you need to know the ID number of a page or post in WordPress and it can be more painful than it should be to find that number. This plugin does one simple thing: it displays the ID number of the page, post, category, or tag you are looking at in the WordPress Admin Bar. It appends this ID to the edit menu already on the Admin Bar. Needless to say, that means that this plugin is only useful for WordPress version 3.1 or above, since the Admin Bar was first introduced with 3.1.

Admin Bar ID Menu

Makes the ID number of the current page or post visible in the Admin Bar.

Aaron T. Grogg

This plug-in limits the classes WordPress added to navigation menus to only those desired by the Theme owner, 
adds a unique ID to each <code>li</code> and removes any empty <code>class</code> attributes.
More about this plug-in can be found at: 
http://aarontgrogg.com/2011/09/28/wordpress-plug-in-navigation-menu-ids-classes/
Please let me know if you have any questions/suggestions/thoughts,
Atg

Navigation Menu IDs & Classes

At least some aspect of this plugin seems like it should be available in WordPress core. 
I understand the rationale for menu items having menu-item-ID, but it's pretty practical for them to have the slug in there, as this plugin provides.
Suggestion for plugin feature - offer option for slug prefix.
Like if I have a menu item "updates" I may use the class "updates" elsewhere, but class "menu-item-updates" would target the menu-item for sure. Of course I can currently use double selectors.



1 for inclusion in core

To reduce the extraneous WordPress classes and add unique IDs to navigation menus.

Admin Bar ID Menu vs Navigation Menu IDs & Classes