Anyway, to expand on that style a little, here's how I usually run what I call 'Twilight Mafia', because the reactions I get are priceless.
The werewolf team has the power of misdirection, at least one member of the team shows up to the seer as a regular villager, and the village has at least one lycan (villager that reveals as a werewolf) in play. They also have the advantage of knowing who they attacked. If that player doesn't die, there's a chance they were either a special villager worth saving or a vampire.
The vampires cannot be killed during the night phase. Not by werewolf attacks, not by poisoning. Any attack on a vampire will be treated the same as one that was blocked by a bodyguard. The only way to get rid of a vamp is during the day.
Either team can only win when the other is completely gone, and they match/beat the village in numbers. Every night, each team gets a chance to kill. To make up for it, the village tends to have a variety of powers, a few extra potions for the witch, a bodyguard, and so on.
One spin I also really like, if the players are particularly skilled, is to use a variant on the seer. Rather than picking one player to learn the role of, the seer picks two, and learns whether they are on the same team or not.