Horror movies like:

The Texas Chainsaw Massacre

The Exorcist

Halloween

Not even one mention of all the cheesy German pornos? Boo! =P

dr strangelove is a 1964 movie
kubriek only made 3 movies in the 70's

a clockwork orange ( 1971 )

boring pardon barry lyndon ( 1975 )

and the shining which was released in 1980 but took all of 1979 to shoot

I'm not sure I get what your point is. If you don't like generalizations or have a problem with the term "classical music", that's fine, but you could have read the whole paragraph you're quoting and find I specifically named Sibelius' Valse Triste and Ravel's Bolero, two well known "orchestral" "20th century" compositions for "acoustic instruments", so you had right there an answer to your three questions.

Yes, quite right -- my mistake.

Five Easy Pieces

The Passenger

Barry Lyndon

Dog Day Afternoon

Network

Apocalypse Now

Most of the ones I'd mention have already been mentioned. Some that I didn't notice (though they may have been mentioned already)...

Superman (1978) The first one is classic. Much better than what came after.

Smokey and the Bandit (once again, first one is better than what came after).

Prior to Cannonball run was a movie called Gumball Rally (1976)

And one I like but most probably don't would be a Star Wars Knock Off...

Battlestar Galactica (cinema version).

well, some people here pretty much posted the majority of the repertoire of good movies from that era, but some personal favorites of mine by far that still withstand the test of time are:

The Godfather (1,2)

Halloween '78

Apocalypse Now

The Conversation

One Flew over the Cuckoo's Nest.

Felt Conversation ended too quickly, though. As for One Flew over the Cuckoo's Nest nothing beats the end with Jack Nicholson and Chief. Too heartbreaking beyond words.