Any edged weapon wielded by someone who knows how to use it. Frankly it's the intent and skill of the attacker that bothers me more than what he may be attacking with.
Edged weapons in the hands of a determined and skilled assailant are SCARY.
As an aside: my father in law, nephew, and I were talking on the way home Friday night from a rather successful bowhunt. I had bagged a small 8 pointer and my nephew had bagged a doe. Perfect through the vitals shots on both. My truck was literally dripping blood out the back as we were driving home. Seeing once again what a razor sharp broadhead does to flesh in comparison to a bullet, I told him, "If I ever get shot I hope it's with a gun and not a bow." He agreed.
I'm not sure there's a surgeon out there who could repair the damage done by a well placed broadhead, yet we hear stories of individuals surviving gunshot wounds that "should" have been fatal.
Yeah, I think I'd rather have a bullet...