There's a million different scores for Nosferatu ranging from mind-numbingly inappropriate to perfection. The best score I've heard is one attatched to the archive.org print. No credit but it's great. There's also a pipe organ one that's good.

It's always important to research... a ton of silent films have surviving "cue sheets" which note what kind of music should be played when. Most silent films never had official scores, but a handful did - Metropolis' orchestral score is so perfectly timed, nothing can beat it. D.W. Griffith intended The Birth of a Nation to have a certain type of score (it had one composed by Joseph Carl Breill).

Some films depend on appropriate music... Intolerance has a synthesizer score - but it's EPIC. It absolutely needs an orchestral score (one exists for the Thames laserdisc/tape). On the other hand, The Unknown (Lon Chaney) has sort of an avant-garde synth track that's absolutely perfect for the film because of the weird nature of the film.

You just have to tread lightly. I'm going to be preparing some edited music tracks for some GBStv silents coming up (The General), but I'm going to research to make sure it fits appropriately.