Flight of the Valkyries. Fortunate Son is a great second. Now can someone put the song’s they’ve listed to the movies they were in? Flight is from Apocalypse Now, Fortunate Son is from Forrest Gump.
Surfin’ Bird is from Full Metal Jacket
Instead of “Run to the Hills,” I’d go with “The Prisoner” … 
How about the theme to ‘Airwolf’?
Mine weren’t from any films, they’re just what I’m listening to at the moment.
addition:
“The Hate Song” - Raging Speedhorn.
That’s easy:
Groovin’ - The Rascals Platoon
Surfin’ Bird - The Trashmen - Full Metal Jacket
Wooly Bully - Sam the Sham & the Pharaohs - Full Metal Jacket
Nowhere to Run - Martha Reeves -Good Morning Vietnam: The Original Motion Picture Soundtrack
I Got You (I Feel Good) - James Brown-Good Morning Vietnam: The Original Motion Picture Soundtrack
Fortunate Son - CCR - Forest Gump
Suzie Q - Flash Cadillac-Apocalypse Now Redux
American Woman - The Guess Who -Vietnam: Songs from a Divided House
War - Edwin Starr -Vietnam: Songs from a Divided House
IMHO, Metalica and Iron Maiden are a poor choice for that ride into the bush cause it just gets everyone even more wired up.
See, I was imagining a situation more akin to the Desert Strike video game, where you just get to kill everything in sight, and so I was imagining what music I would want to blare out of the front speakers to scare the people who I was about to kill.
I had thought it was a unique peculiarity of mine that there are a number of songs that have developed this association in my head.
Of course, the internet has shown us that there are no unique peculiarities…
My sampler, mostly post-Nam, for flying into battle, guns blazing and rockets ripple-firing:
“Dragula” – Rob Zombie
“Gel” – Collective Soul
“Zero” – Smashing Pumpkins
“Nightcrawler” – Judas Priest
“The Hunt” theme from Jerry Goldsmith’s score for The Final Conflict
or, for cheerier, more whimiscal devastation –
“Daydream Believer” – The Monkees
“Take a Chance on Me” – ABBA
“This Kiss” – Faith Hill
For cruising over the jungle/rice paddies/etc., in a variety of moods:
“The Sun Ain’t Gonna Shine Anymore” – The Walker Brothers
“You’ve Got Another Thing Coming” – Judas Priest
“No Surrender” – Bruce Springsteen
“Shadows of the Night” – Pat Benatar
“Twilight Zone” – Golden Earring
If you want a classical score, you could steal most of the psy-ops torture list from Eric Flint’s 1632:
Wozzeck - Berg
Night on Bald Moutain - Mussorgsky
Pictures at an Exhibition “Bydlo” - Mussorgsky
Peer Gynt “In the Hall of the Mountain King” - Greig
Alexander Nevsky “Arise, ye Russian People” - Prokofiev
Piano Concert #3 - Prokofiev
The Rite of Spring - Stravinsky
Tristan & ISolde’s “Liebestod” - Wagner
Der Ring “Entry of the Gods Into Valhalla” - Wagner
Der Ring “Ride of the Valkyries” - Wagner
Der Ring “Wotan’s Farewell” - Wagner
Der Ring “Siegried’s Funeral March” - Wagner
Der Ring “Immolation of the Gods” - Wagner
Symphony #8 - Shostakovich
And yes, I did just post something similar to the Iraqi musical torture thread, but it fits nicely here too.
I’d want some good opera, NOT Wagner - but I repeat myself. I just think some nice, heartbreakingly beautiful music would be just the thing to go with large-scale death and destruction.
I was thinking “American Badass” by Kid Rock.
“Gimmie Shelter” - The Rolling Stones
Mark Twain observed that “Wagner’s music is better than it sounds.”
I have GOT to lay off that “Lord Julius’ Ring Around the Bathtub Gin.”
“Great new label, same funny aftertaste” indeed.
I should think that Wagner’s “Liebestod”, as recommended by NameAlreadyTaken, would fit the bill nicely, whatever your prejudices.
The “Ode to Joy” from Beethoven’s Ninth would seem to hit the right note, though it’s become a running gag in the Die Hard movies.
How about some show tunes? Some brassy stuff like “Everything’s Comin’ Up Roses” from Gypsy, or “Oklahoma”, or “One” from A Chorus Line, could be a good tongue-in-cheek counterpoint to carnage…
Since no one has mentioned it, in Predator, future Senator Ventura is playing “Long Tall Sally” by Little Richard.
My personal choice would be “Voodoo Chile (Slight Return)” - opening scratch during slo-mo advancing scene, opening wailing guitar during close-ups of the guys in the chopper, slow drum beats during scene of unsuspecting village, then when the drums and jammin’ guitar kick in, asses kickin’. 
He also said, on his way out of some opera or another, “I haven’t heard anything like that since the orphanage burned down.”
Back to the OP, For that familiar Vietman era gunship swoop, I’d suggest:
Time - Chambers Brothers
Try (Just a Little Bit Harder) - Janis Joplin
Locomotive Breath - Jethro Tull
40,000 Headmen - Traffic
Reach Out - The Four Tops
Let’s Live for Today - Grassrooots (on second thought, perhaps not)
I’d also like to add Immigrant Song by Led Zepplin. I hate their music but that song is a good one to play when in your gunship blowing things up.
But what about for after you land during your post-traumatic stress disorder? How about:
Veteran of the Psychic Wars - Blue Oyster Cult
Spiral - Jesus Jones
One - Metallica
Vietnam: Last Time Around - The Del-Vetts
Now: Anything by The Hellacopters
Has to be Paint it Black, but I’ll only say it once. That opening sequence was one of the best parts of “Tour of Duty”.