The stereotype that we have no social aptitude. I, personally, have very little, but I have friends who are very social and also play plenty of videogames.
Also, shooters in general. The genre of first person shooting has evolved significantly in that they often give narratives and create an identifiable environment for the player. It's gotten much more complex than the electronic stress ball that was the original DOOM. Not that DOOM wasn't a good game, but I have a hard time convincing non-gamers that shooters have in fact evolved from such humble beginnings.