iTunes is great for keeping all your music organized but it's oddly lacking a visual browsing component. Sometimes you just want to flip thru album covers and discover an old favorite or even something new. Coverflow is tight little application for the Mac that presents a simple interface for searching and browsing your music by album cover. When you find something to listen to just use the built in controls to play thru iTunes. There's also a handy utility for finding and adding missing album art.