Ok - "Kill 'em All" came from Cliff Burton referring to distributors who didn't like what they were doing, or how they were doing something (can't remember exactly, maybe the original album title, below), and Cliff supposedly said in passing "We should just kill 'em all". It was originally supposed to be named Metal Up Your Ass with a picture of a toilet with a blade coming up from inside, but the label didn't like that. 
