Okay here it is... After EXTENSIVE RESEARCH (I asked people on twitter what they reckoned) I proudly present (and then immediately duck behind the nearest sofa) the Great Library Stereotypometer - a new, up-to-date, piercingly accurate and entirely NON-SERIOUS look at library stereotypes!
As the caption says, click it to view full-size. Feel free to use it anywhere. Don't take it seriously. (Seriously.)
More to add? Why not create your own! :)