Honestly I think no music would work in a horror game. Absolutely none. Ever. If its just you trotting through a creepy building with no music then you become very aware of your surrounding and every creaking door, drafty window, and sound in nature becomes terrifying.
Also I think we've come to expect music so having none might be rather unsettling.
Also one of the creepiest music moments for me was in world 3-1 of Demon's Souls. At one point about 1/3 through the level you start to hear a woman singing. There hadn't really been any music in the level up to that point and this level already scared the piss out of me but when I heard this chick start singing I was flipping out. Best of all NOTHING happened. There were essentially no threats in the area where you could hear the music. Still scared me shitless though.
Also I think we've come to expect music so having none might be rather unsettling.
Also one of the creepiest music moments for me was in world 3-1 of Demon's Souls. At one point about 1/3 through the level you start to hear a woman singing. There hadn't really been any music in the level up to that point and this level already scared the piss out of me but when I heard this chick start singing I was flipping out. Best of all NOTHING happened. There were essentially no threats in the area where you could hear the music. Still scared me shitless though.