When you create any website usability is an essential goal, and usable and user friendly navigation is something every website needs.
It will give options to interact with the site easily.
Below I present some excellent navigation menus .

1] Sexy Drop Down Menu w/ jQuery & CSS

Nice jquery menu created by Soh Tanaka

2] Apple style menu

Nice Apple style menu with sliding effect.

3] Color Fading Menu

Nice jquery menu with fading effect.

Horizontal Animated Menu

This tutorial shows you how to create an interactive animated horizontal menu using jQuery that shows more information about particular link when mouse is moved over it.

Sliding Menu using jQuery