Depends on your attitude and preferences. JS can look very cool but a pure CSS can be much faster.
I mostly follow this mantra: If the client can disable it, don't use it

So I generally use pure CSS/HTML methods
I'll post some tutorial links that can help you out
Pure CSS
Code:
http://csswizardry.com/2011/02/creating-a-pure-css-dropdown-menu/
Code:
http://sperling.com/examples/menuh/
CSS and JQuery
Code:
http://www.noupe.com/tutorial/drop-down-menu-jquery-css.html