There isn't a single pinball machine that personifies the whole pinball genre. With video arcade games, pacman is universal.
I tend to disagree with Addams and Twilight Zone being the poster children. Only people in the hobby point to those and medieval Madness as required pinball games. Most lay people have never even played them!
When you say to someone you have video games, they will probably say one of 2 things:
"Do you have a Pacman?"
"Do you have a Golden Tee?" (I finally got this one from a Uhaul employee one day)
If you tell a non hobbyist you are into pinballs, odds are they will draw a blank as to a specific title. If there was a pinball that would jump to mind, I would venure a guess of Pinbot. It had additional exposure via the NES port. Of course, many people that had the NES game probably didn't realize it was based on a REAL pinball machine.
My guess as to why this is, is because most people who have played pinball don't pay attention to rules or graphics. They see 2 flippers, a shiny ball, a bunch of flashy lights, and a bunch of crap to slam said ball into. Every pinball is basically the same. I've realized this in my gameroom. Most people don't give a crap what the theme of the pinball is - they just think its cool that there is a pinball they can play without spending money.