The next advance in winamp skinning is out and people are already switching over to this way of skinning winamp modern skins the Old School way. Why is this news? In the past you had the 2 sides Winamp1 vs Winamp3-5. ClassicPro od Cpro people call it.
ClassicPro© skins is basically just another type of Winamp skin. It heart its a modern skin but the way new skins are developed is similar to the way you'll make a classic skin.
ClassicPro is a plugin that you'll need to install in order to use any cPro skin. Atm ClassicPro skins is only SingleUserInterface skins, like Bento for Winamp 5.5. At a later stage another type of ClassicPro skin might be added to the installer that might include a non SUI layout.
As you might notice, ClassicPro skins use very little CPU power. Hit F5 to see how quick it loads. Compare this to some other Modern skins in your collection to see the difference.