This is the soundtrack from Takashi Shimizu's 'The Grudge'. It is very dissonant and it is very suspenseful. The beginning section really creates tension and is quite chilling. It then builds up and becomes more orchestral. I think it is quite suitable for our thriller opening.
This is the soundtrack from M. Night Shyamalan's thriller 'The Happening', I really like this soundtrack, it starts off soft, with a piano riff that plays throughout the whole soundtrack, it then builds up to a climax and becomes orchestral like the first one, which is quit suitable for our thriller opening, which gets more and more anticipating as it goes.
This is the soundtrack from Gore Verbinski's 'The Ring'. By beginning soft and calm, then ending loud and more orchestral, the composer, Hans Zimmer, makes the soundtrack more intense. The meandering motifs with a harp build the suspense and make it more thrilling.
I have noticed that most of the thriller film soundtracks begin soft and then build up to a climax, becoming more orchestral and loud. This is a good technique as it creates suspense and is chilling, a good way to keep the audience on the end of their seats. I think that it would be a good convention to add to our thriller soundtrack.