Script editor. Why? So I can get scripts, and have infinite fun telling the writer why he is Bad At Writing. Instead of a pen/tippex to cross out bad/unnecessary/otherwise stupid lines, I'd have a paint-roller. And white paint.
"...This page is dreadful, as is this, I like this bit but the rest of the page is awful, I'm setting this disgrace to writing on fire, here, catch." Ah, it'd be like being Bernard Black, only working as a script editor.
Of course, I'd have to not be able to be fired. Or sued. Or murdered by bitter writers.