9. Phased-Plasma Rifle in the 40-Watt Range - The Terminator

Even though we don't ever see this gun in action, the mere mention of it so blows the mind of Mr. Futterman the Gun Shop Owner that we just know we have to have one. And the fact that the Terminator walks out of the store with enough firepower to invade Cuba and still seems disappointed tells you all you need to know.