Suspiria
I had the pleasure of watching this on the Synapse 4K release. I can't believe how beautiful it is.
Dario Argento is a master of color, suspense, drama, and craft on this one. Jessica Harper is undeniably amazing and deserves all the praise in the world too. Plus the Goblin score is undefeated as well.
I'm not positive this surpasses my love for Opera but watching in these conditions has it firmly in 1A/1B position.