A few composers stand out for me....
Ennio Morricone- 'The Good, The Bad and The Ugly', 'Once Upon A Time In The West' and 'A Fistful Of Dynamite'; all of these are superb pieces of film music, yet are some kind of weird psychedelic mutation of Western movie scores.
John Barry- a plethora of great works; much my favourites are 'On Her Majesty's Secret Service' (best Bond film and soundtrack ever!), 'Game Of Death' (a clear case of where the soundtrack is better than the film, an exploitative Bruce Lee movie which is kind of so bad it's good...), 'You Only Live Twice' (blissful), 'The Ipcress File', plus his wonderful, Moog heavy theme tune to classic TV show 'The Persuaders'...
Roy Budd- did some great action movies; 'The Stone Killer' (underrated Charles Bronson cop thriller- lots of Moog/ heavy rock weirdness), 'Get Carter' (haunting and eerie- a perfect soundtrack to arguably THE greatest UK gangster film).
Laurie Johnson- more of a composer of TV themes, but I just love the themes for 'The Avengers', 'The New Avengers' and 'The Professionals'. There's much incidental music throughout these however, with lots of heavy funk wah wah workouts on the latter two. For a piece of camp charm, check out his theme for 'Jason King' too...