Silver goes well back into werewolf lore. It is about purity. Moons are tidal; studies show the full moon effects plants, animals and nature--so it actually adds a believable quality.
However, I've read a number of books that do not follow this cliche line of reasoning. They should have a wider variety of source facts, though:
1) Winter, statistically, is the time of year when most werewolf sightings have been reported.
2) There are a number of ways to become a werewolf--exchange of fluids (any fluids), Seventh Son of a Seventh Son, Bastard child of a priest, a magic girdle, sleeping next to a powerful wolf, drinking from a powerful wolf's pawprint, a pact with the devil or wearing of a ceremonial skin.
3) Legends of werewolves are so widespread that only areas that have never heard of a wolf don't have them; they have werecats.
I also find it STUPID to have a rave full of werewolves. Hmm, better seeing and smelling but not hearing...duh.