Some websites that feature this style of navigation are the following:
     http://office.microsoft.com/en-us/default.aspx
     http://www.computerhope.com/
     http://freelancer.internet.com/

This style is useful because its easy to use and very organized by distributing all of the content into sections making it easy for the visitor to find what they are looking for.

Index navigation

     http://www.flamencoshop.com/
     http://www.global-links.org/main.htm
     http://www.homepages.dsu.edu/jankej/civilwar/civilwar.htm

If done correctly, this style of navigation can be useful when a website has a lot of information. This would make a website with a lot of content more organized by creating separate links to separate portions of the website.

Pull-Down Menu

     http://javascript.internet.com/navigation/menu.html
     http://drakehs.org/
     http://tamdistrict.schoolwires.net/tamalpais/site/default.asp

This style of menu can be practical if you were thinking about putting many menus on your website. This is because it organizes the menus into categories and makes it easier to navigate.

My favorite style of menu is the Tab-Stop menu because its useful for websites with little content and its also very easy to create for beginner web designers.