I just usually talk about the horrible naughty girl monster that will eat her face off if she continues to be bad...then thump my foot on the floor and tell her the monster is coming up the back stairway... seems to do the trick...
Kidding -- (ok, I did it once, but I felt REALLY bad afterwards) the punishment fits the crime in our house. They either get verbally reprimanded, time-outs, flicked on the hand (or leg if they're kicking), "warning" patted (1/2 spank), or spanked on the butt. We don't make a big production of it and we swat at the time of indiscresion. We do try to positively reinforce our kids... i.e. not "if you don't eat your dinner, you can't watch Little Mermaid", we're "if you eat all your dinner like a big girl, you get to watch Little Mermaid!"