Imagine a boat without a compass, that is what a webpage would be without navigation.
Without proper navigation a user would get lost in the jungle of sites and not find way to the content he wishes to see.
Navigation is more than just placing fancy icons and buttons with cool fonts to link sites.
To build a smart navigation one needs to start with the information architecture and continue until the entire design process.
A good navigation is a good IA in itself.
Remember to use names that are short and self explanatory, also try to use common conventions such as home, about us, contact us, etc.