Okay, since we've detoured from Mob Films onto general films, here's a few more scores I love:
Once Upon a Time In the West/America by Ennio Morricone
Cinema Paradiso by Ennio Morricone
The Battle of Algiers by Ennio Morricone
A bout de souffle by Martial Solal
North by Northwest, Vertigo, Citizen Kane, Taxi Driver, by Bernard Herrmann.
Blue Velvet, Twin Peaks, Mulholland Dr. by Angelo Badalamenti.
Also, the soundtracks for 2001 and A Clockwork Orange.
Mick