Here's something I had a lot of fun putting together with the new Garritan Instant Orchestra Library.
First version - A fairly literal rendition of a famous strings passage you'll recognize. I used various new strings patches from IO, like "alt bows short attack," "marcato strings alt" and "Col Legno full strings"--
You can hear from that demo that getting aggressive attacks on your strings is very possible with IO.
Second version - The above, but with other IO patches layered on top, such as "Horrid Choir" "Scary Piano" and "Weirdness"--
Instant Orchestra gives you plenty to work with for creating horror film soundtracks.