Visual Complexity is a vertible warehouse of over 200 examples of representations of complex networks.
It is a fascinating site in that it makes explicit the complexity that underlies seemingly simple things. Take high school social networks and look at the image above. Hmmm. See that little dot over by itself on the left....that's me.
Actually what can be gleaned from this image is that white people (in white) hang around with other white people (mostly) and african-americans (in green) with other african-americans (mostly) and that everyone else fits in all over the place (at this one particular school).
Some of the images are hard to read and understand. Some are full of overlapping images and we can't really make sense of them. But, in some instances, that may actually be the point.
(Almost Forgot: Thanks, Jayme)