Destroyer of Nazi Teddy Bears
I want those simply because they sound fucking awesome. Not to mention they kick total ass in Deus ExI want a pair of assassin's hidden mounted arm blades, for just such an occasion that somebody tries to knock me down in the street. Because generally, seeing two blades appear on your opponent suddenly is enough to make you pause and re-assess the situation. Even if it does stall them for only a second, that's one more second that I have to get the fuck out of there.
I used to collect swords and shit, some movie replicas. I stopped because they are fuckall expensive. But, there are a few exceptions I would make. Something like that would be one of them. A set of Predator blades would be the other.