Without any bias whatsoever, i can state categorically that the finest film score was premiered last night at Brecon Film Society, Wales (for which i happen to be publicist). Special musical accompaniment composed and performed by Paul Shallcross, a perfect match to Buster Keaton's silent masterpiece The General. 

A magnificent silent score that comes to mind is Henri Rabaud's to the little known, marvellous The Chess Player (Bernard, 1927).

Ennio Morricone (Once upon a Time in America/ The West...)and Bernard Herrmann (Vertigo, North by Northwest, Citizen Kane, Taxi Driver...) are the 2 top names, for me.