So many goods ideas. Hmm....

[quote=Zerofighter]
 A guy's best friend is bitten by a mysterous wolf Only it was too big to be one. Now she is slowly becoming a shewolf. She begins to be more aggressive, and more protective of her friend. Her canines are sharper, and her eyes turn yellow. Her eears become more pointed and she grows a tail. Soon she is a shewolf.(Kinda like a neko only instead of a human-cat its a human wolf) Her friend devides to take care of her like a pet. 

A serial killer falls for this guy. She loves him to death and will do anything to be with him. She kills any girl that gets close to him and wont let anyone hurt him. She watches him sleep and even lays next to him in bed. 

 A vampiress meets a boy. They get on perfectly and she falls for him. She likes him because if his scent and because of how kind he is. They enter a relationship and She tells him and he is fine with her. He even offers to be her 'bloodbank' but there are rumors of a hunter coming. 
[/quote]

These would have to be my top three though. Feel free to drop me a PM with more details.