What is the most important component in your audio chain?

Bear with me for a moment and I'll get to the point. When I was sixteen my father bought me my first stereo. It was a Silvertone from Sears that looked like a suitcase. Two 2-way speakers unhooked from the sides and the top opened a phonograph. It cost $100.

I took the stereo with me to college. A lot of new and exciting music was coming out in the early sixties. Getz/Gilberto blew me away. I discovered jazz and new rock n' roll. After spending the first night with my girlfriend, I stood on the bed naked and conducted Stravinsky's Firebird. This is not gratuitous because it is a metaphor for what I'm about to say. I never enjoyed any stereo as much as my Silvertone.Why was it the most enjoyable stereo for me? Because of the most important component in the audio chain--the meat between my ears. 

I now have $70,000 plus in stereo equipment (not to mention all the $ I've spent learning what sound I liked and being able to afford that sound), but I will never again have the youthful mind exploring a fresh and vibrant world of music and life. 

I will soon be 78. I spend mornings and early afternoons writing and listening to music. I think it was Irving Stone who did a sampling of his writer friends and found out that 1/2 liked to write to silence while the other half needed music. Fortunately, I'm the half that needs music. And every now and then (once every few weeks if I'm lucky) that 17-year-old boy standing naked on his bed conducting the Firebird arises in me and the meat between my ears tingles with joy. Truthfully, I don't need a $70K system for that to happen.