To use the KDE4 eye candy, you don't have to do much. You can activate the effects under System Settings and Desktop. Then you go to All effects and activate cover switch. I really like how it displays the windows while flipping through them with alt-tab.
You can also let it snow on your desktop, show stars around the mouse cursor, etc. And with a simple click you can add one of the high (and probably quickly increasing) number of kde4 plasma widgets, also known as plasmoids.