the Candide Overtoure, by Leonard Bernstein
(here is Bernstein himself directing)
Man DavidMahler was in before me on the Mahler recommendation.
Ahh well here's my rocked out Mahler pick. Symphony 2 the Resurrection - jeez could it be any bigger and heavy? Wow. And Bernstein is an utter bada**.
Tchaikovsky's Symphony 6 Pathetique. - My favorite symphony ever. So many feelings are hit in just the first movement alone. Anger, misery, despair, hatred, anxiety. Emotions that metal can often evoke. Lovin' it.
Hey, am I the first to mention Alexander Mosolov's The Iron Foundry? It's not just metal, it's extreme metal! (Or perhaps simply Industrial.)
Actually, I think most, if not all, good classical music is metal-like. It shares the same emotional intensity.