Of course you don't have to stick to the plain vanilla examples above. Who We Are What We Do Where to Find Us Is also perfectly alright, but I wouldn't go much farther out than that. Again, the purpose of your site is to provide information, not to entertain with word games. Do your users a favor and make it clear what they'll get when they click on a link. If your site features downloadable files, audio or video links, or other bandwidth hogs, list the file size next to each link so users will know what they're getting into.
Most sites use a hierarchical arrangement.
A hierarchy may be thought of as a triangle, with the home page at the top corner, and the lowest level of detail as the bottom edge of the triangle. If your home page links to twenty pages, you should add another level. Of course, some sections of your site may have more levels than others. This is partly a matter of opinion, and varies greatly from one site to another. Some people believe that lengthy content, which if placed on a single page would require readers to scroll down several screens to see it all, should be broken up into several pages.