Worms. It'd be the worlld of Worms for me. Old women explode when they start talking, so you don't have to listen to them for an eternity. And you can throw bananas at other people without them getting mad (they won't even know what hit them before they die). And you never run out of ninja ropes! In ourr world you never have a ninja rope when you really need one...

Probably Shivering Isles for me. . . I'd feel right at home with those crack-pots.