Need Theory on how to approach an MC directory

Right now I am in the stages of actually planning out how to do this, so no scripting, just need more of an idea on how to build this. basically There will be 1 movie clip directory and movie clip buttons inside. when clicked upon they will load external swfs within a placeholder. now the question is… what would be the best way to go about building this?
here is a link of the effect I want to try and create:

http://www.sony.com

OK: look at thier top navigation (drop down menu’s) I found tutorials on how to make a directory with the traditional buttons, but the purpose of my project is to create a clean, drop down menu with smooth transistions of the buttons when you roll over or click on them. Anyone know the best way to approach this so that I won’t be stuck with endless timeline and layers… there has to be an easier way without getting confused.:cons: