What I can think of, in no particular order.

Openings:
Dark Tranquility - Punish My Heaven (gets the song going, but doesn't sound all too raw)
Entombed - Chief Rebel Angel (both the noise and the intro riff. Especially love the noise)
Opeth - The Drapery Falls (Just a niiice build up)
Ac/Dc - Thunderstruck (sure, not metal, but it's good)

Closings:
Opeth - Deliverance
Entombed - Chief Rebel Angel (just the lovely noise again)

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