Navigate through application that have windows shortcut cmd+tab navigates through all open applications.
Some Apps can have no windows at all e.g. firefox, finder.
Is there a shortcut for navigating through only applications that have at least one window?
The closest built-in option in OS X is to launch Expose which shows all open windows, then hit the tab key to cycle through all open apps.  It will still select those with no open windows, but is a quick alternative nonetheless.