Page Links To
A lot of WordPress themes put in a non-editable bar at the top listing your pages. This is a really nice feature as it saves you time for editing it, but what if you want a link on there to go somewhere else? Well that is where the Page Links To plugin comes in.
The Page Links To plugin puts an option menu at the bottom of your page editor, that allows you to specify a different link for the page to go to. This way you can create a space holder page so the name shows up, then link it to somewhere else. Extremely useful if you want to say link to a category or an external link.
So if you have run into this problem before, or just want to make linking in your site a little more versatile, I would highly recommend taking a look at the Page Links To plugin. You never know when this option might be just what you were looking for.