I mean for me, this will probably always be it...
SNIP
I used to go to a lot of metal shows on the infamous Lamour's in Brooklyn. Not sure how I got in at such a young age but I did.
They would play music in between bands sets and every. single. time this song came on the crowd went nuts. So maybe that shaped my perspective of things, but that is about as metal of an intro as it gets.
At the gates - Slaughter of the soul
Duh duh duh duh duh
GO!!!
I'll go with a classic, Holy Diver by Dio. 1min 30secs of ambient fear noises before the song unleashes sacrilegious licks