As many young website designers do, when I first got started working with HTML and CSS, I tired to stay as far away from Unordered Lists (<ul>) and Ordered Lists (<ol>). Everyone has their own reasons, but I just thought there was too much to learn about it before I could get it to do what I want.
When you have a list of items, links, etc., it should be in a list
I found this amazing article about lists on AListApart.com: Taming Lists
(Lists are also what you would use to create a pop-up menu only using CSS.)