For our first example, you can look at this somewhat large banner and menu setup: http://www.spirecorp.com/ Another example comes courtesy of Midwest Seed GeNetics. Also, the Bureau of Engraving and Printing uses a catchy banner with two different menus underneath.
Of course the basic idea can be modified in various ways. Consider the more lateral approach made by Audrey's Claddagh Irish Jewelry. Nor do things have to be at all rectangular. Look at the Pratt Institute's page.
Some sites use HTML frames to partition the screen. Ken & Tiffani's WedSite used this approach.