What Is and What Should Never Be by Led Zeppelin

This song was the reason I got fancy headphones when I was in my early 20s. The build, the stereo, the classic Page & Plant complement. The absolute best part is when everything but the guitar cuts away at about the 3.5 minute mark and you are listening to guitar ricocheting across what seems like the walls of your skull. Then all of a sudden BAM! It all comes back together with Robert Plant wailing and a steady John Bonham drum beat taking you out to the end of the song.