My son the movie buff (well, minor in film studies, major in English) mentions "Psycho" as his favourite instrumental score and "The Graduate" as a good one-artist score. My wife likes "Robin Hood, Prince of Thieves" (lots of other things wrong with that movie, but the music was good). For folkies, I'd mention "Matewan" (Hazel Dickens' graveside hymn is breathtaking) as well as the aforementioned "Songcatcher", O Brother Where Art Thou" and "Barry Lyndon" (The Chieftains' first score, if memory serves).