Aiight, so I'm trying to write a song for my band. However, I'm stumped...because I don't know what key it should be in. Any suggestions?

P.S. The song's gonna be called "Sympathy for the Perpetrator," and I'm thinking of a kind of Nine Inch Nails-meets-Asking Alexandria thing. (If you're not familiar with them, Trent Reznor of NIN is known for his sensitive, emotional lyrics; and Asking Alexandria is a metalcore band.)