Not only is Halloween coming up, but Movember is too! Why not kill two birds with one stone and grow a moustache for both occasions. My suggestion is the Daniel Day-Lewis from 'Gangs of New York'.
Not only would it work well in the context of a costume, but it would remain stylish for all of November as well.
Movember is a yearly event that runs during the month of november where men grow moustaches to help raise money to cure prostate cancer. Prostate cancer is one of the leading causes of death in men, so it's definitely for a good cause.
There's a website dedicated to it that you can check out here: