I think navigation bars and dropdown menus can be problematic.
Sometimes, when confronted with a dropdown menu, many users' attention is drawn to the options in the dropdown menu and overlook the main link entirely. This may not be a huge problem…unless the main menu item is linked to a page you really don't want users to overlook.
Here's what I mean:
Can't see the video? Watch it here.
In order to make sure users don't overlook important content on your site, duplicate the link that functions as your main menu item right in the dropdown menu as well.
It may seem a bit redundant to you as the site owner, but in the end, I think it ensures users don't accidentally miss what you really want them to see.